CVE-2026-63795
CVE CVE-2026-63795EUVD EUVD-2026-45461Published 2026-07-19T12:02:04.000ZLast changed 2026-08-05T12:35:44.000ZCVSS 10.0
What the advisory describes
In the Linux kernel, the following vulnerability has been resolved: 9p: avoid putting oldfid in p9_client_walk() error path When p9_client_walk() is called with clone set to false, fid aliases oldfid. If the walk subsequently fails after the request has been sent, the error path jumps to clunk_fid, which currently calls p9_fid_put(fid) unconditionally. This drops a reference to oldfid even though ownership of oldfid remains with the caller. If this is the last reference, oldfid can be clunked and destroyed while the caller still expects it to be valid. A later use or put of oldfid can then trigger a use-after-free or refcount underflow. Fix this by only putting fid in the clunk_fid error path when it does not alias oldfid, matching the existing guard in the error path below. This can be triggered when a multi-component walk is split into multiple p9_client_walk() calls and a later non-cloning walk fails. A reproducer and refcount warning logs are available on request.
Source: EUVD (ENISA), in the words of the advisory.
Products the advisory names
These come from the advisory itself, not from any check we performed.
- Linux — Linux patch: 6.1.177; b48dbb998d70b7f48c2ec0a15c3cf47136808e4e <1a3860d46e3eb47dbd60339783cdad7904486b9f; 6.0; patch: 7.2-rc1; patch: 6.12.95; b48dbb998d70b7f48c2ec0a15c3cf47136808e4e <99c379ca1e221c3d75c7c804ebbf4e5ee37a3070; b48dbb998d70b7f48c2ec0a15c3cf47136808e4e <b84f46179c806450b89821221ea5bd9a1698aba8; b48dbb998d70b7f48c2ec0a15c3cf47136808e4e <a7656d368265d085ac9bb85ab31b0cdb72ad8c38; patch: 6.18.38; patch: 7.1.3; patch: 6.6.144; b48dbb998d70b7f48c2ec0a15c3cf47136808e4e <6dbe9443d9f5f7fb6d319a7b77108853ae6c6bea; patch: 0; b48dbb998d70b7f48c2ec0a15c3cf47136808e4e <a61bdcba4f64c2f90d01461913f429ab151f1ca6
The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.
Carried in the product catalogue
An estate covering these products can be recorded in Patchlage. An advisory about them appears in the next morning's situation report.
- Linux — Linux
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