CVE-2026-90151

/// Technical description

In the Linux kernel, the following vulnerability has been resolved:

NFSv4: remove callback IDR entry on client allocation failure

nfs4_alloc_client() allocates an NFSv4.0 callback identifier before it

finishes setting up the client. If any later initialization step fails,

the error path frees the nfs_client directly with nfs_free_client(). That

bypasses nfs_put_client(), which is where the callback IDR entry is

removed during normal teardown.

A failed allocation can therefore leave cb_ident_idr pointing at a freed

nfs_client. A later NFSv4.0 callback lookup by cb_ident would find the

stale pointer and take a reference to it.

Make the callback IDR removal helper callable by the allocation failure

path, and remove the callback identifier before freeing the client.

This was found by a local static-analysis checker for publish-before-free

lifetime bugs and confirmed by manual inspection.

/// 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