{"schema_version":"1.7.2","id":"OESA-2026-4483","modified":"2026-10-22T14:35:40Z","published":"2026-10-22T14:35:40Z","upstream":["CVE-2025-62231","CVE-2026-34002","CVE-2026-34003","CVE-2026-50257","CVE-2026-50258","CVE-2026-50259","CVE-2026-50260","CVE-2026-50261","CVE-2026-50262","CVE-2026-50263","CVE-2026-55999"],"summary":"xorg-x11-server-xwayland security update","details":"Xwayland is an X server for running X clients under Wayland.   %package devel Summary: Development package Requires: pkgconfig   %description devel The development package provides the developmental files which are necessary for developing Wayland compositors using Xwayland.   %prep %autosetup -n xwayland- -p1   %build %meson \\         -Ddefault_font_path="catalogue:/etc/X11/fontpath.d,built-ins" \\         -Dbuilder_string="Build ID:  -" \\         -Dxkb_output_dir=/lib/xkb \\         -Dxcsecurity=true \\         -Dglamor=true \\         -Ddri3=true   %meson_build\r\n\r\nSecurity Fix(es):\n\nA flaw was identified in the X.Org X server’s X Keyboard (Xkb) extension where improper bounds checking in the XkbSetCompatMap() function can cause an unsigned short overflow. If an attacker sends specially crafted input data, the value calculation may overflow, leading to memory corruption or a crash.(CVE-2025-62231)\n\nA flaw was found in the X.Org X server. This vulnerability, an out-of-bounds read, affects the XKB (X Keyboard Extension) modifier map handling. An attacker with access to the X11 server can exploit this by sending a malformed request, which causes the server to read beyond its intended memory boundaries. This can lead to the exposure of sensitive information or cause the server to crash, resulting in a denial of service.(CVE-2026-34002)\n\nA flaw was found in the X.Org X server's XKB key types request validation. A local attacker could send a specially crafted request to the X server, leading to an out-of-bounds memory access vulnerability. This could result in the disclosure of sensitive information or cause the server to crash, leading to a Denial of Service (DoS). In certain configurations, higher impact outcomes may be possible.(CVE-2026-34003)\n\n['Hi all,\\n\\nCVEs have been issued now, please see inline below\\n\\nOn Tue, Jun 02, 2026 at 10:01:46AM +1000, Peter Hutterer wrote:', "=======================================================================\\nX.Org Security Advisory: June 2, 2026 \\n\\nIssues in X.Org X server prior to 21.1.23 and Xwayland prior to 24.1.12\\n=======================================================================\\n\\nMultiple issues have been found in the X server and Xwayland implementations\\npublished by X.Org for which we are releasing security fixes for in\\nxorg-server-21.1.23 and xwayland-24.1.12.\\n\\nNote that CVEs have been requested for these issues but did not get assigned in\\ntime for this disclosure.\\n\\n* Font Alias Stack-based Buffer Overflow\\n\\n    A mismatch between the X server and the libXfont2 library's maximum\\n    font name length can cause a stack buffer overflow during font alias\\n    resolution. The server allocates a 256 byte stack buffer but libXfont2's\\n    alias target name length is 1024 bytes. A font alias name between 257\\n    and 1023 bytes causes the X server to copy that name into the undersized\\n    stack buffer without further checks.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:", 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30136)', 'This issue has been assigned CVE-2026-50256', '* XSYNC Use-After-Free in miSyncDestroyFence()\\n\\n    A client that sets up multiple fence triggers can trigger a\\n    use-after-free function pointer call. An attacker would connect to the\\n    X server to set up a fence and await that fence, then a second X\\n    connection destroys the fence, causing the use-after-free.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30159)', 'This issue has been assigned CVE-2026-50257', '* XKB Key Types Stack-based Buffer Overflow\\n\\n    The X server has multiple stack buffers that are sized\\n    XkbMaxShiftLevel * XkbNumKbdGroups but CheckKeyTypes() does not verify\\n    or clamp non-canonical key types to XkbMaxShiftLevel. A client can\\n    change key types to excessive shift levels and trigger three separate\\n    stack overflows.\\n\\n    This is caused by an incomplete fix of CVE-2025-26597.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30160)', 'This issue has been assigned CVE-2026-50258', '* XKB SetMap Request Stack-based Buffer Overflow\\n\\n    _XkbSetMapChecks() declares a fixed-size stack buffer mapWidths[256]\\n    indexed by key type index. The helper function CheckKeyTypes() writes\\n    to this buffer at a client-controlled offset, allowing a stack buffer\\n    overflow.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30161)', 'This issue has been assigned CVE-2026-50259', '* XSYNC Use-After-Free in FreeCounter()\\n\\n    A client that sets up multiple SyncCounters and awaits on those\\n    triggers can trigger a use-after-free when destroying those counters\\n    via a second client connection.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30163)', 'This issue has been assigned CVE-2026-50260', '* XSYNC Use-After-Free in SyncChangeCounter()\\n\\n    A client that sets up multiple SyncCounters can trigger a use-after-free\\n    when destroying those counters via a second client connection while\\n    changing those counters.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30164)', 'This issue has been assigned CVE-2026-50261', '* GLX ChangeDrawableAttributes Out-Of-Bounds Read/Write\\n\\n    A wrong size validation check in __glXDisp_ChangeDrawableAttributes()\\n    can read (or write) a client-contr(CVE-2026-50257)\n\n['Hi all,\\n\\nCVEs have been issued now, please see inline below\\n\\nOn Tue, Jun 02, 2026 at 10:01:46AM +1000, Peter Hutterer wrote:', "=======================================================================\\nX.Org Security Advisory: June 2, 2026 \\n\\nIssues in X.Org X server prior to 21.1.23 and Xwayland prior to 24.1.12\\n=======================================================================\\n\\nMultiple issues have been found in the X server and Xwayland implementations\\npublished by X.Org for which we are releasing security fixes for in\\nxorg-server-21.1.23 and xwayland-24.1.12.\\n\\nNote that CVEs have been requested for these issues but did not get assigned in\\ntime for this disclosure.\\n\\n* Font Alias Stack-based Buffer Overflow\\n\\n    A mismatch between the X server and the libXfont2 library's maximum\\n    font name length can cause a stack buffer overflow during font alias\\n    resolution. The server allocates a 256 byte stack buffer but libXfont2's\\n    alias target name length is 1024 bytes. A font alias name between 257\\n    and 1023 bytes causes the X server to copy that name into the undersized\\n    stack buffer without further checks.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:", 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30136)', 'This issue has been assigned CVE-2026-50256', '* XSYNC Use-After-Free in miSyncDestroyFence()\\n\\n    A client that sets up multiple fence triggers can trigger a\\n    use-after-free function pointer call. An attacker would connect to the\\n    X server to set up a fence and await that fence, then a second X\\n    connection destroys the fence, causing the use-after-free.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30159)', 'This issue has been assigned CVE-2026-50257', '* XKB Key Types Stack-based Buffer Overflow\\n\\n    The X server has multiple stack buffers that are sized\\n    XkbMaxShiftLevel * XkbNumKbdGroups but CheckKeyTypes() does not verify\\n    or clamp non-canonical key types to XkbMaxShiftLevel. A client can\\n    change key types to excessive shift levels and trigger three separate\\n    stack overflows.\\n\\n    This is caused by an incomplete fix of CVE-2025-26597.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30160)', 'This issue has been assigned CVE-2026-50258', '* XKB SetMap Request Stack-based Buffer Overflow\\n\\n    _XkbSetMapChecks() declares a fixed-size stack buffer mapWidths[256]\\n    indexed by key type index. The helper function CheckKeyTypes() writes\\n    to this buffer at a client-controlled offset, allowing a stack buffer\\n    overflow.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30161)', 'This issue has been assigned CVE-2026-50259', '* XSYNC Use-After-Free in FreeCounter()\\n\\n    A client that sets up multiple SyncCounters and awaits on those\\n    triggers can trigger a use-after-free when destroying those counters\\n    via a second client connection.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30163)', 'This issue has been assigned CVE-2026-50260', '* XSYNC Use-After-Free in SyncChangeCounter()\\n\\n    A client that sets up multiple SyncCounters can trigger a use-after-free\\n    when destroying those counters via a second client connection while\\n    changing those counters.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30164)', 'This issue has been assigned CVE-2026-50261', '* GLX ChangeDrawableAttributes Out-Of-Bounds Read/Write\\n\\n    A wrong size validation check in __glXDisp_ChangeDrawableAttributes()\\n    can read (or write) a client-contr(CVE-2026-50258)\n\n['Hi all,\\n\\nCVEs have been issued now, please see inline below\\n\\nOn Tue, Jun 02, 2026 at 10:01:46AM +1000, Peter Hutterer wrote:', "=======================================================================\\nX.Org Security Advisory: June 2, 2026 \\n\\nIssues in X.Org X server prior to 21.1.23 and Xwayland prior to 24.1.12\\n=======================================================================\\n\\nMultiple issues have been found in the X server and Xwayland implementations\\npublished by X.Org for which we are releasing security fixes for in\\nxorg-server-21.1.23 and xwayland-24.1.12.\\n\\nNote that CVEs have been requested for these issues but did not get assigned in\\ntime for this disclosure.\\n\\n* Font Alias Stack-based Buffer Overflow\\n\\n    A mismatch between the X server and the libXfont2 library's maximum\\n    font name length can cause a stack buffer overflow during font alias\\n    resolution. The server allocates a 256 byte stack buffer but libXfont2's\\n    alias target name length is 1024 bytes. A font alias name between 257\\n    and 1023 bytes causes the X server to copy that name into the undersized\\n    stack buffer without further checks.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:", 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30136)', 'This issue has been assigned CVE-2026-50256', '* XSYNC Use-After-Free in miSyncDestroyFence()\\n\\n    A client that sets up multiple fence triggers can trigger a\\n    use-after-free function pointer call. An attacker would connect to the\\n    X server to set up a fence and await that fence, then a second X\\n    connection destroys the fence, causing the use-after-free.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30159)', 'This issue has been assigned CVE-2026-50257', '* XKB Key Types Stack-based Buffer Overflow\\n\\n    The X server has multiple stack buffers that are sized\\n    XkbMaxShiftLevel * XkbNumKbdGroups but CheckKeyTypes() does not verify\\n    or clamp non-canonical key types to XkbMaxShiftLevel. A client can\\n    change key types to excessive shift levels and trigger three separate\\n    stack overflows.\\n\\n    This is caused by an incomplete fix of CVE-2025-26597.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30160)', 'This issue has been assigned CVE-2026-50258', '* XKB SetMap Request Stack-based Buffer Overflow\\n\\n    _XkbSetMapChecks() declares a fixed-size stack buffer mapWidths[256]\\n    indexed by key type index. The helper function CheckKeyTypes() writes\\n    to this buffer at a client-controlled offset, allowing a stack buffer\\n    overflow.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30161)', 'This issue has been assigned CVE-2026-50259', '* XSYNC Use-After-Free in FreeCounter()\\n\\n    A client that sets up multiple SyncCounters and awaits on those\\n    triggers can trigger a use-after-free when destroying those counters\\n    via a second client connection.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30163)', 'This issue has been assigned CVE-2026-50260', '* XSYNC Use-After-Free in SyncChangeCounter()\\n\\n    A client that sets up multiple SyncCounters can trigger a use-after-free\\n    when destroying those counters via a second client connection while\\n    changing those counters.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30164)', 'This issue has been assigned CVE-2026-50261', '* GLX ChangeDrawableAttributes Out-Of-Bounds Read/Write\\n\\n    A wrong size validation check in __glXDisp_ChangeDrawableAttributes()\\n    can read (or write) a client-contr(CVE-2026-50259)\n\n['Hi all,\\n\\nCVEs have been issued now, please see inline below\\n\\nOn Tue, Jun 02, 2026 at 10:01:46AM +1000, Peter Hutterer wrote:', "=======================================================================\\nX.Org Security Advisory: June 2, 2026 \\n\\nIssues in X.Org X server prior to 21.1.23 and Xwayland prior to 24.1.12\\n=======================================================================\\n\\nMultiple issues have been found in the X server and Xwayland implementations\\npublished by X.Org for which we are releasing security fixes for in\\nxorg-server-21.1.23 and xwayland-24.1.12.\\n\\nNote that CVEs have been requested for these issues but did not get assigned in\\ntime for this disclosure.\\n\\n* Font Alias Stack-based Buffer Overflow\\n\\n    A mismatch between the X server and the libXfont2 library's maximum\\n    font name length can cause a stack buffer overflow during font alias\\n    resolution. The server allocates a 256 byte stack buffer but libXfont2's\\n    alias target name length is 1024 bytes. A font alias name between 257\\n    and 1023 bytes causes the X server to copy that name into the undersized\\n    stack buffer without further checks.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:", 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30136)', 'This issue has been assigned CVE-2026-50256', '* XSYNC Use-After-Free in miSyncDestroyFence()\\n\\n    A client that sets up multiple fence triggers can trigger a\\n    use-after-free function pointer call. An attacker would connect to the\\n    X server to set up a fence and await that fence, then a second X\\n    connection destroys the fence, causing the use-after-free.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30159)', 'This issue has been assigned CVE-2026-50257', '* XKB Key Types Stack-based Buffer Overflow\\n\\n    The X server has multiple stack buffers that are sized\\n    XkbMaxShiftLevel * XkbNumKbdGroups but CheckKeyTypes() does not verify\\n    or clamp non-canonical key types to XkbMaxShiftLevel. A client can\\n    change key types to excessive shift levels and trigger three separate\\n    stack overflows.\\n\\n    This is caused by an incomplete fix of CVE-2025-26597.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30160)', 'This issue has been assigned CVE-2026-50258', '* XKB SetMap Request Stack-based Buffer Overflow\\n\\n    _XkbSetMapChecks() declares a fixed-size stack buffer mapWidths[256]\\n    indexed by key type index. The helper function CheckKeyTypes() writes\\n    to this buffer at a client-controlled offset, allowing a stack buffer\\n    overflow.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30161)', 'This issue has been assigned CVE-2026-50259', '* XSYNC Use-After-Free in FreeCounter()\\n\\n    A client that sets up multiple SyncCounters and awaits on those\\n    triggers can trigger a use-after-free when destroying those counters\\n    via a second client connection.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30163)', 'This issue has been assigned CVE-2026-50260', '* XSYNC Use-After-Free in SyncChangeCounter()\\n\\n    A client that sets up multiple SyncCounters can trigger a use-after-free\\n    when destroying those counters via a second client connection while\\n    changing those counters.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30164)', 'This issue has been assigned CVE-2026-50261', '* GLX ChangeDrawableAttributes Out-Of-Bounds Read/Write\\n\\n    A wrong size validation check in __glXDisp_ChangeDrawableAttributes()\\n    can read (or write) a client-contr(CVE-2026-50260)\n\n['Hi all,\\n\\nCVEs have been issued now, please see inline below\\n\\nOn Tue, Jun 02, 2026 at 10:01:46AM +1000, Peter Hutterer wrote:', "=======================================================================\\nX.Org Security Advisory: June 2, 2026 \\n\\nIssues in X.Org X server prior to 21.1.23 and Xwayland prior to 24.1.12\\n=======================================================================\\n\\nMultiple issues have been found in the X server and Xwayland implementations\\npublished by X.Org for which we are releasing security fixes for in\\nxorg-server-21.1.23 and xwayland-24.1.12.\\n\\nNote that CVEs have been requested for these issues but did not get assigned in\\ntime for this disclosure.\\n\\n* Font Alias Stack-based Buffer Overflow\\n\\n    A mismatch between the X server and the libXfont2 library's maximum\\n    font name length can cause a stack buffer overflow during font alias\\n    resolution. The server allocates a 256 byte stack buffer but libXfont2's\\n    alias target name length is 1024 bytes. A font alias name between 257\\n    and 1023 bytes causes the X server to copy that name into the undersized\\n    stack buffer without further checks.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:", 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30136)', 'This issue has been assigned CVE-2026-50256', '* XSYNC Use-After-Free in miSyncDestroyFence()\\n\\n    A client that sets up multiple fence triggers can trigger a\\n    use-after-free function pointer call. An attacker would connect to the\\n    X server to set up a fence and await that fence, then a second X\\n    connection destroys the fence, causing the use-after-free.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30159)', 'This issue has been assigned CVE-2026-50257', '* XKB Key Types Stack-based Buffer Overflow\\n\\n    The X server has multiple stack buffers that are sized\\n    XkbMaxShiftLevel * XkbNumKbdGroups but CheckKeyTypes() does not verify\\n    or clamp non-canonical key types to XkbMaxShiftLevel. A client can\\n    change key types to excessive shift levels and trigger three separate\\n    stack overflows.\\n\\n    This is caused by an incomplete fix of CVE-2025-26597.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30160)', 'This issue has been assigned CVE-2026-50258', '* XKB SetMap Request Stack-based Buffer Overflow\\n\\n    _XkbSetMapChecks() declares a fixed-size stack buffer mapWidths[256]\\n    indexed by key type index. The helper function CheckKeyTypes() writes\\n    to this buffer at a client-controlled offset, allowing a stack buffer\\n    overflow.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30161)', 'This issue has been assigned CVE-2026-50259', '* XSYNC Use-After-Free in FreeCounter()\\n\\n    A client that sets up multiple SyncCounters and awaits on those\\n    triggers can trigger a use-after-free when destroying those counters\\n    via a second client connection.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30163)', 'This issue has been assigned CVE-2026-50260', '* XSYNC Use-After-Free in SyncChangeCounter()\\n\\n    A client that sets up multiple SyncCounters can trigger a use-after-free\\n    when destroying those counters via a second client connection while\\n    changing those counters.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30164)', 'This issue has been assigned CVE-2026-50261', '* GLX ChangeDrawableAttributes Out-Of-Bounds Read/Write\\n\\n    A wrong size validation check in __glXDisp_ChangeDrawableAttributes()\\n    can read (or write) a client-contr(CVE-2026-50261)\n\n['Hi all,\\n\\nCVEs have been issued now, please see inline below\\n\\nOn Tue, Jun 02, 2026 at 10:01:46AM +1000, Peter Hutterer wrote:', "=======================================================================\\nX.Org Security Advisory: June 2, 2026 \\n\\nIssues in X.Org X server prior to 21.1.23 and Xwayland prior to 24.1.12\\n=======================================================================\\n\\nMultiple issues have been found in the X server and Xwayland implementations\\npublished by X.Org for which we are releasing security fixes for in\\nxorg-server-21.1.23 and xwayland-24.1.12.\\n\\nNote that CVEs have been requested for these issues but did not get assigned in\\ntime for this disclosure.\\n\\n* Font Alias Stack-based Buffer Overflow\\n\\n    A mismatch between the X server and the libXfont2 library's maximum\\n    font name length can cause a stack buffer overflow during font alias\\n    resolution. The server allocates a 256 byte stack buffer but libXfont2's\\n    alias target name length is 1024 bytes. A font alias name between 257\\n    and 1023 bytes causes the X server to copy that name into the undersized\\n    stack buffer without further checks.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:", 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30136)', 'This issue has been assigned CVE-2026-50256', '* XSYNC Use-After-Free in miSyncDestroyFence()\\n\\n    A client that sets up multiple fence triggers can trigger a\\n    use-after-free function pointer call. An attacker would connect to the\\n    X server to set up a fence and await that fence, then a second X\\n    connection destroys the fence, causing the use-after-free.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30159)', 'This issue has been assigned CVE-2026-50257', '* XKB Key Types Stack-based Buffer Overflow\\n\\n    The X server has multiple stack buffers that are sized\\n    XkbMaxShiftLevel * XkbNumKbdGroups but CheckKeyTypes() does not verify\\n    or clamp non-canonical key types to XkbMaxShiftLevel. A client can\\n    change key types to excessive shift levels and trigger three separate\\n    stack overflows.\\n\\n    This is caused by an incomplete fix of CVE-2025-26597.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30160)', 'This issue has been assigned CVE-2026-50258', '* XKB SetMap Request Stack-based Buffer Overflow\\n\\n    _XkbSetMapChecks() declares a fixed-size stack buffer mapWidths[256]\\n    indexed by key type index. The helper function CheckKeyTypes() writes\\n    to this buffer at a client-controlled offset, allowing a stack buffer\\n    overflow.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30161)', 'This issue has been assigned CVE-2026-50259', '* XSYNC Use-After-Free in FreeCounter()\\n\\n    A client that sets up multiple SyncCounters and awaits on those\\n    triggers can trigger a use-after-free when destroying those counters\\n    via a second client connection.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30163)', 'This issue has been assigned CVE-2026-50260', '* XSYNC Use-After-Free in SyncChangeCounter()\\n\\n    A client that sets up multiple SyncCounters can trigger a use-after-free\\n    when destroying those counters via a second client connection while\\n    changing those counters.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30164)', 'This issue has been assigned CVE-2026-50261', '* GLX ChangeDrawableAttributes Out-Of-Bounds Read/Write\\n\\n    A wrong size validation check in __glXDisp_ChangeDrawableAttributes()\\n    can read (or write) a client-contr(CVE-2026-50262)\n\n['Hi all,\\n\\nCVEs have been issued now, please see inline below\\n\\nOn Tue, Jun 02, 2026 at 10:01:46AM +1000, Peter Hutterer wrote:', "=======================================================================\\nX.Org Security Advisory: June 2, 2026 \\n\\nIssues in X.Org X server prior to 21.1.23 and Xwayland prior to 24.1.12\\n=======================================================================\\n\\nMultiple issues have been found in the X server and Xwayland implementations\\npublished by X.Org for which we are releasing security fixes for in\\nxorg-server-21.1.23 and xwayland-24.1.12.\\n\\nNote that CVEs have been requested for these issues but did not get assigned in\\ntime for this disclosure.\\n\\n* Font Alias Stack-based Buffer Overflow\\n\\n    A mismatch between the X server and the libXfont2 library's maximum\\n    font name length can cause a stack buffer overflow during font alias\\n    resolution. The server allocates a 256 byte stack buffer but libXfont2's\\n    alias target name length is 1024 bytes. A font alias name between 257\\n    and 1023 bytes causes the X server to copy that name into the undersized\\n    stack buffer without further checks.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:", 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30136)', 'This issue has been assigned CVE-2026-50256', '* XSYNC Use-After-Free in miSyncDestroyFence()\\n\\n    A client that sets up multiple fence triggers can trigger a\\n    use-after-free function pointer call. An attacker would connect to the\\n    X server to set up a fence and await that fence, then a second X\\n    connection destroys the fence, causing the use-after-free.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30159)', 'This issue has been assigned CVE-2026-50257', '* XKB Key Types Stack-based Buffer Overflow\\n\\n    The X server has multiple stack buffers that are sized\\n    XkbMaxShiftLevel * XkbNumKbdGroups but CheckKeyTypes() does not verify\\n    or clamp non-canonical key types to XkbMaxShiftLevel. A client can\\n    change key types to excessive shift levels and trigger three separate\\n    stack overflows.\\n\\n    This is caused by an incomplete fix of CVE-2025-26597.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30160)', 'This issue has been assigned CVE-2026-50258', '* XKB SetMap Request Stack-based Buffer Overflow\\n\\n    _XkbSetMapChecks() declares a fixed-size stack buffer mapWidths[256]\\n    indexed by key type index. The helper function CheckKeyTypes() writes\\n    to this buffer at a client-controlled offset, allowing a stack buffer\\n    overflow.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30161)', 'This issue has been assigned CVE-2026-50259', '* XSYNC Use-After-Free in FreeCounter()\\n\\n    A client that sets up multiple SyncCounters and awaits on those\\n    triggers can trigger a use-after-free when destroying those counters\\n    via a second client connection.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30163)', 'This issue has been assigned CVE-2026-50260', '* XSYNC Use-After-Free in SyncChangeCounter()\\n\\n    A client that sets up multiple SyncCounters can trigger a use-after-free\\n    when destroying those counters via a second client connection while\\n    changing those counters.\\n\\n    Fixed in: xorg-server-21.1.23 and xwayland-24.1.12\\n    Fix:', 'Found by: Anonymous working with TrendAI Zero Day Initiative.\\n              (ZDI-CAN-30164)', 'This issue has been assigned CVE-2026-50261', '* GLX ChangeDrawableAttributes Out-Of-Bounds Read/Write\\n\\n    A wrong size validation check in __glXDisp_ChangeDrawableAttributes()\\n    can read (or write) a client-contr(CVE-2026-50263)\n\nLocal attackers with an X connection able to provide PCX fonts to the X server xorg-server before 21.2.24 and xwayland before 24.1.13 could cause a heap buffer overflow via SetFont due to missing glyph boundary checks.(CVE-2026-55999)","affected":[{"package":{"ecosystem":"openEuler:24.03-LTS-SP4","name":"xorg-x11-server-xwayland","purl":"pkg:rpm/openEuler/xorg-x11-server-xwayland&distro=openEuler-24.03-LTS-SP4"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"xorg-x11-server-Xwayland-22.1.2-20.oe2403sp4"}]}],"ecosystem_specific":{"aarch64":["xorg-x11-server-Xwayland-22.1.2-20.oe2403sp4.aarch64.rpm","xorg-x11-server-Xwayland-debuginfo-22.1.2-20.oe2403sp4.aarch64.rpm","xorg-x11-server-Xwayland-debugsource-22.1.2-20.oe2403sp4.aarch64.rpm","xorg-x11-server-Xwayland-devel-22.1.2-20.oe2403sp4.aarch64.rpm"],"src":["xorg-x11-server-Xwayland-22.1.2-20.oe2403sp4.src.rpm"],"x86_64":["xorg-x11-server-Xwayland-22.1.2-20.oe2403sp4.x86_64.rpm","xorg-x11-server-Xwayland-debuginfo-22.1.2-20.oe2403sp4.x86_64.rpm","xorg-x11-server-Xwayland-debugsource-22.1.2-20.oe2403sp4.x86_64.rpm","xorg-x11-server-Xwayland-devel-22.1.2-20.oe2403sp4.x86_64.rpm"]}}],"references":[{"type":"ADVISORY","url":"https://www.openeuler.org/zh/security/security-bulletins/detail/?id=openEuler-SA-2026-4483"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-62231"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-34002"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-34003"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-50257"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-50258"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-50259"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-50260"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-50261"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-50262"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-50263"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-55999"}],"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H"}],"database_specific":{"severity":"Critical"}}