A logic flaw (Fragnesia) in the Linux kernel's XFRM ESP-in-TCP subsystem (CVE-2026-43503, CVSS 8.8 HIGH) allows local privilege escalation or container escape via socket buffer fragment handling. Affected kernel versions include 3.9 through 5.10.256, 5.11 through 5.15.207, 5.16 through 6.1.173, 6.2 through 6.6.140, and 6.7 through 6.12.90. The flaw is fixed in kernel versions 5.10.257, 5.15.208, 6.1.174, 6.6.141, 6.12.91, 6.18.33, and 7.0.10.
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) 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: - InfiniBand drivers; - STMicroelectronics network drivers; - NVME drivers; - SCSI subsystem; - USB over IP driver; - Network file system (NFS) server daemon; - SMB network file system; - Tracing infrastructure; - B.A.T.M.A.N. meshing protocol; - Ethernet bridge; - Ceph Core library; - IPv4 networking; - IPv6 networking; - Netfilter; - RxRPC session sockets; - X.25 network layer; (CVE-2026-23272, CVE-2026-23455, CVE-2026-31402, CVE-2026-31418, CVE-2026-31607, CVE-2026-31637, CVE-2026-31649, CVE-2026-31659, CVE-2026-31682, CVE-2026-31685, CVE-2026-43011, CVE-2026-43037, CVE-2026-43038, CVE-2026-43117, CVE-2026-43383, CVE-2026-43407, CVE-2026-43414, CVE-2026-45988, CVE-2026-46043, CVE-2026-46119, CVE-2026-46135, CVE-2026-46243)