Always-Incorrect Control Flow Implementation in Linux kernel - CVE-2026-72166
Published: August 16, 2026
Vulnerability details
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to improper signal handling in p9_client_rpc() in net/9p/client.c when handling P9_TFLUSH requests over an fd transport with no peer. A local user can trigger a fatal signal while a thread is blocked in the affected code path to cause a denial of service.
The issue can cause the affected task to sleep indefinitely and, in practice, can stall coredump handling in multi-threaded processes.
Affected software
Ubuntu
linux-nvidia (Ubuntu package)
linux-gcp-7.0 (Ubuntu package)
linux (Ubuntu package)
linux-oem-7.0 (Ubuntu package)
linux-azure-7.0 (Ubuntu package)
linux-azure (Ubuntu package)
How to mitigate CVE-2026-72166
linux-nvidia (Ubuntu package) - addressed in versions 5.15.0-1112.113, 5.15.0.1112.112
linux-gcp-7.0 (Ubuntu package) - addressed in versions 7.0.0-38.38~24.04.4, 7.0.0-1013.13~24.04.1, 7.0.0-1014.14~24.04.1
linux (Ubuntu package) - addressed in versions 7.0.0-38.38, 7.0.0-38.38.1, 7.0.0-1008.9, 7.0.0-1013.13~24.04.1, 7.0.0-1014.14, 7.0.0-1015.15
linux-oem-7.0 (Ubuntu package) - update to 7.0.0-1015.15
linux-azure-7.0 (Ubuntu package) - addressed in versions 7.0.0-1016.16~24.04.1, 7.0.0-1017.17~24.04.1
linux-azure (Ubuntu package) - addressed in versions 7.0.0-1016.16, 7.0.0-1017.17
External References
- https://git.kernel.org/stable/c/378481cc60a937ef8ea4ef6e4f95f0dbc4e21414
- https://git.kernel.org/stable/c/4f621ae3a2d99b0bac50e8d66cbf7f68323c01e8
- https://git.kernel.org/stable/c/6b4f48728faa8bb514368f7eacda05565dea8696
- https://git.kernel.org/stable/c/823886a1b089b49bcd349bc8bd3417b7910cd1ac
- https://git.kernel.org/stable/c/a8874c34c4a973f9922908a4b8be1d1278f01e42
- https://git.kernel.org/stable/c/dc892cbb1e4341d427b1f940ebd6abd69bf8e479
- https://git.kernel.org/stable/c/f62a1f245a71680033260a6f6d74011cc3acb3cd