CVE-2026-53394

/// Technical 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.

/// Remediation

Check the references section for vendor advisories, patches, and mitigation guidance. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.

/// References