CVE-2026-53394
nfsd: avoid leaking pre-allocated openowner on unconfirmed retry race
- State
- Published
- Severity
- 7.5 High
- Published
- Jul 19, 2026
- Updated
- Oct 19, 2026
- Reserved
- Jun 9, 2026
Description
In the Linux kernel, the following vulnerability has been resolved:
nfsd: avoid leaking pre-allocated openowner on unconfirmed retry race
When find_or_alloc_open_stateowner() encounters an unconfirmed owner, it calls release_openowner() and sets oo = NULL. Control then falls through past the `if (oo)` guard -- which would have freed any pre-allocated `new` -- and unconditionally executes `new = alloc_stateowner(...)`. If `new` was already allocated on a prior iteration, the pointer is silently overwritten and the previous allocation (slab object + owner name buffer) is leaked.
This requires a race: two NFSv4.0 OPEN threads with the same owner string, where a concurrent thread inserts a new unconfirmed owner into the hash between retry iterations. The window is narrow but repeatable under adversarial conditions.
Fix by adding `goto retry` after `oo = NULL` so the already-allocated `new` is reused on the next iteration rather than overwritten.
Scores
| CVSS | Score | Vector | Source |
|---|---|---|---|
| 3.1 | 7.5 High | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H | Linux |
Weaknesses
- CWE-401 Missing Release of Memory after Effective Lifetime
Affected Products
| Product | Versions |
|---|---|
LinuxLinux |
|
LinuxLinux |
|
References
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