An update for edk2 is now available for openEuler-24.03-LTS-SP3 Security Advisory openeuler-security@openeuler.org openEuler security committee openEuler-SA-2026-2891 Final 1.0 1.0 2026-07-09 Initial 2026-07-09 2026-07-09 openEuler SA Tool V1.0 2026-07-09 edk2 security update An update for edk2 is now available for openEuler-24.03-LTS-SP3 EDK II is a modern, feature-rich, cross-platform firmware development environment for the UEFI and PI specifications. Security Fix(es): Issue summary: When EVP_PKEY_derive_set_peer() is called with a DHX (X9.42) peer key, the peer key is not properly checked for the subgroup membership. Impact summary: A malicious peer which presents an X9.42 key carrying the victim's p and g parameters, a forged q = r (a small prime factor of the cofactor (p−1)/q_local), and a public value Y of order r can recover the victim's private key after a small number of key exchange attempts. When EVP_PKEY_derive_set_peer() is called with a DHX (X9.42) peer key, the subgroup membership check Y^q ≡ 1 (mod p) is performed using the peer's own q parameter, not the local key's q. The peer's domain parameters are then matched against the domain parameters of the private key, but the value of q is not compared. A malicious peer who presents an X9.42 key carrying the victim's p, g, a forged q = r (a small prime factor of the cofactor), and a public value Y of order r passes all checks. The shared secret then takes only r distinct values, leaking priv mod r. Repeating for each small-prime factor of the cofactor and combining via CRT recovers the full private key (Lim–Lee / small-subgroup-confinement attack). The realistic attack surface is narrow: principally CMP deployments with long-lived RA/CA DHX keys and bespoke enterprise or government applications using X9.42 DHX static keys with interactive protocols and therefore this issue was assigned Low severity. The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are affected by this issue.(CVE-2026-42770) An update for edk2 is now available for openEuler-24.03-LTS-SP3. openEuler Security has rated this update as having a security impact of low. A Common Vunlnerability Scoring System(CVSS)base score,which gives a detailed severity rating, is available for each vulnerability from the CVElink(s) in the References section. Low edk2 https://www.openeuler.org/zh/security/security-bulletins/detail/?id=openEuler-SA-2026-2891 https://www.openeuler.org/en/security/cve/detail/?cveId=CVE-2026-42770 https://nvd.nist.gov/vuln/detail/CVE-2026-42770 openEuler-24.03-LTS-SP3 edk2-debuginfo-202308-43.oe2403sp3.aarch64.rpm edk2-debugsource-202308-43.oe2403sp3.aarch64.rpm edk2-devel-202308-43.oe2403sp3.aarch64.rpm edk2-debuginfo-202308-43.oe2403sp3.x86_64.rpm edk2-debugsource-202308-43.oe2403sp3.x86_64.rpm edk2-devel-202308-43.oe2403sp3.x86_64.rpm edk2-aarch64-202308-43.oe2403sp3.noarch.rpm edk2-help-202308-43.oe2403sp3.noarch.rpm edk2-ovmf-202308-43.oe2403sp3.noarch.rpm python3-edk2-devel-202308-43.oe2403sp3.noarch.rpm Issue summary: When EVP_PKEY_derive_set_peer() is called with a DHX (X9.42) peer key, the peer key is not properly checked for the subgroup membership. Impact summary: A malicious peer which presents an X9.42 key carrying the victim's p and g parameters, a forged q = r (a small prime factor of the cofactor (p−1)/q_local), and a public value Y of order r can recover the victim's private key after a small number of key exchange attempts. When EVP_PKEY_derive_set_peer() is called with a DHX (X9.42) peer key, the subgroup membership check Y^q ≡ 1 (mod p) is performed using the peer's own q parameter, not the local key's q. The peer's domain parameters are then matched against the domain parameters of the private key, but the value of q is not compared. A malicious peer who presents an X9.42 key carrying the victim's p, g, a forged q = r (a small prime factor of the cofactor), and a public value Y of order r passes all checks. The shared secret then takes only r distinct values, leaking priv mod r. Repeating for each small-prime factor of the cofactor and combining via CRT recovers the full private key (Lim–Lee / small-subgroup-confinement attack). The realistic attack surface is narrow: principally CMP deployments with long-lived RA/CA DHX keys and bespoke enterprise or government applications using X9.42 DHX static keys with interactive protocols and therefore this issue was assigned Low severity. The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are affected by this issue. 2026-07-09 CVE-2026-42770 openEuler-24.03-LTS-SP3 Low 3.7 AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N edk2 security update 2026-07-09 https://www.openeuler.org/zh/security/security-bulletins/detail/?id=openEuler-SA-2026-2891