This USN-8426-1 security advisory details multiple high-severity Linux kernel vulnerabilities affecting Azure kernels, including the "Copy Fail" flaw in the algif_aead module (CVE-2026-31431, CVSS 7.8), "Dirty Frag" logic flaws in XFRM and RxRPC subsystems (CVE-2026-43284, CVSS 8.8; CVE-2026-43500, CVSS 7.8), and a race condition in the ptrace subsystem (CVE-2026-46333). These local attack vectors enable privilege escalation or container escape. Affected version ranges are extensive; for example, CVE-2026-31431 impacts kernel versions from 4.14 up to but excluding 5.10.254, 5.11 up to 5.15.204, and similarly through multiple major branches, with fixes available in specific versions like 5.10.254, 5.15.204, and 6.1.170.
It was discovered that the Linux kernel algif_aead module did not properly handle in-place cryptographic operations. This flaw is known as Copy Fail. A local attacker could use this to escalate privileges, or possibly escape a container. (CVE-2026-31431) It was discovered that the Linux kernel did not properly handle shared page fragments during socket buffer operations, collectively known as Dirty Frag. A logic flaw existed in the XFRM ESP-in-TCP subsystem and in the RxRPC networking subsystem when processing paged fragments. A local attacker could use this to escalate privileges, or possibly escape a container. (CVE-2026-43284, CVE-2026-43500) It was discovered that a logic flaw existed in the XFRM ESP-in-TCP subsystem in the Linux kernel when handling socket buffer fragments. This flaw is known as Fragnesia. A local attacker could use this to escalate privileges, or possibly escape a container. (CVE-2026-43503, CVE-2026-46300) Qualys discovered that a race condition existed in the ptrace subsystem of the Linux kernel when privileged processes are exiting. An unprivileged local attacker could use this issue to expose sensitive information. (CVE-2026-46333) Several security issues were discovered in the Linux kernel. An attacker could possibly use these to compromise the system. This update corrects flaws in the following subsystems: - Cryptographic API; - Ethernet bonding driver; - SMB network file system; - Netfilter; - io_uring subsystem; - Packet sockets; - RDS protocol; - TLS protocol; (CVE-2024-35862, CVE-2024-50060, CVE-2026-23274, CVE-2026-23351, CVE-2026-31419, CVE-2026-31504, CVE-2026-31533, CVE-2026-43033, CVE-2026-43077, CVE-2026-43078, CVE-2026-43494, CVE-2026-46028)