Use-after-free in Linux kernel - CVE-2026-63795
Published: July 21, 2026
Vulnerability identifier: #VU138866
CSH Severity: Low
CVSS v4: 6.8 [CVSS:4.0/AV:L/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N]
CVE-ID: CVE-2026-63795
CWE-ID: CWE-416
Exploitation vector: Local access
Exploit availability:
No public exploit available
Vulnerability details
The vulnerability allows a local user to cause a denial of service.
The vulnerability exists due to a use-after-free in p9_client_walk() when handling a failed non-cloning walk after a request has been sent. A local user can trigger a multi-component walk split into multiple p9_client_walk() calls to cause a denial of service.
The issue occurs because fid may alias oldfid, causing a reference owned by the caller to be dropped while the caller still expects the object to remain valid.
Affected software
Linux kernel
How to mitigate CVE-2026-63795
Install security update from vendor's repository.
Linux kernel - update to 7.0 rc3
External References
- https://git.kernel.org/stable/c/1a3860d46e3eb47dbd60339783cdad7904486b9f
- https://git.kernel.org/stable/c/6dbe9443d9f5f7fb6d319a7b77108853ae6c6bea
- https://git.kernel.org/stable/c/99c379ca1e221c3d75c7c804ebbf4e5ee37a3070
- https://git.kernel.org/stable/c/a61bdcba4f64c2f90d01461913f429ab151f1ca6
- https://git.kernel.org/stable/c/a7656d368265d085ac9bb85ab31b0cdb72ad8c38
- https://git.kernel.org/stable/c/b84f46179c806450b89821221ea5bd9a1698aba8