CVE-2026-89484

/// Technical description

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

lockd: fix NULL dereference on lockowner allocation failure

nlmclnt_locks_init_private() installs NLM file lock operations even when

nlmclnt_find_lockowner() fails to allocate a lockowner. nlmclnt_proc()

then returns -ENOMEM, but the VFS still tears down the partially

initialized file_lock and calls locks_release_private().

That invokes nlmclnt_locks_release_private(), which dereferences

fl->fl_u.nfs_fl.owner and crashes because the owner was never installed.

Clear fl_ops before attempting to initialize the NLM private state, and

install the NLM lock operations only after a lockowner has been allocated

successfully.

/// 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