The USN-8388-1 advisory details multiple high-severity Linux kernel vulnerabilities, including the "Dirty Frag" and "Fragnesia" logic flaws in socket buffer handling within the XFRM ESP-in-TCP and RxRPC subsystems, which allow local privilege escalation or container escape (CVE-2026-43284, CVSS 8.8; CVE-2026-43500, CVSS 7.8). Affected versions include Linux kernels from 4.11 to before 5.10.255, 5.12 to before 5.15.205, 5.16 to before 6.1.171, 6.2 to before 6.6.138, and 6.7 to before 6.12.87 for CVE-2026-43284, and kernels before 6.18.29 and 6.19 to before 7.0.6 for CVE-2026-43500. The fixes are provided in kernel versions 5.10.255, 5.15.205, 6.1.171, 6.6.138, 6.12.87, 6.18.28, and 7.0.5 for the respective branches, with additional patches in 6.18.29 and 7.0.6.
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: - RDS protocol; (CVE-2026-43494)