CVE-2026-89485

CRITICALCVSS 9.8/10EPSS 0.63%

Last modified

CVE-2026-89485 is a critical-severity vulnerability rated 9.8/10 on the CVSS scale. In the Linux kernel, the following vulnerability has been resolved: lockd: pin next file across nlm_inspect_file lock-drop nlm_traverse_files() pins the current file with f_count++ across a mutex_unlock for nlm_inspect_file(), but nothing pins the saved next pointer. A concurrent nlm_release_file() can kfree the next file during the unlock window, and the iterator dereferences freed memory on the next loop step. Pin both current and next before the lock-drop. EPSS estimates a 0.63% chance of exploitation in the next 30 days.

Description

In the Linux kernel, the following vulnerability has been resolved: lockd: pin next file across nlm_inspect_file lock-drop nlm_traverse_files() pins the current file with f_count++ across a mutex_unlock for nlm_inspect_file(), but nothing pins the saved next pointer. A concurrent nlm_release_file() can kfree the next file during the unlock window, and the iterator dereferences freed memory on the next loop step. Pin both current and next before the lock-drop. Advance by swapping the pinned cursors at the end of each iteration so next is always held alive across the unlock. Always call nlm_file_release() after dropping the iteration pin, regardless of whether the file matched the predicate. Use nlm_file_inuse(), which does a live walk of the inode lock list, rather than the cached f_locks field, so skipped files that never ran nlm_inspect_file() are evaluated correctly. Because every file in a hash bucket is now pinned and released, files skipped by the is_failover_file predicate that have no locks, blocks, shares, or external references are deleted during traversal. The old code never evaluated skipped files for cleanup. The new behavior is intentional: such files are stale and should not persist in the table.

Metrics

EPSS Probability
0.63%

48.1th percentile

Probability of exploitation in the next 30 days. Learn more

Affected Software

Source: CNA advisory (CVE.org). NVD analysis pending.

VendorProductVersions
LinuxLinux>= 01df9c5e918ae5559f2d96da0143f8bfbb9e6171, < e3c413f789eaf0170275c7eba523ead73d963f30; >= 01df9c5e918ae5559f2d96da0143f8bfbb9e6171, < 08a455f87b14c7ff22ae3fdadda62a796a3a5572; >= 01df9c5e918ae5559f2d96da0143f8bfbb9e6171, < 550c19222c7132c888e23c9d89079ba1c9bc4cca; >= 01df9c5e918ae5559f2d96da0143f8bfbb9e6171, < 350087f231c11efcd288c310707c40eab63ca583; >= 01df9c5e918ae5559f2d96da0143f8bfbb9e6171, < c24bdb7df2f34bdc38ca8a73796f5acb40f1830c; >= 01df9c5e918ae5559f2d96da0143f8bfbb9e6171, < 41f0a6d31615fcae261bf28a0aa50050dc93a401; >= 01df9c5e918ae5559f2d96da0143f8bfbb9e6171, < e999a88133654c6dfc68487fb49da5f20dfa2d4f; >= 01df9c5e918ae5559f2d96da0143f8bfbb9e6171, < 526c49cff3f72c3ec74752016380c7567040581b
LinuxLinux2.6.18

References

Timeline

Published
Last Modified
Status
Received

Frequently Asked Questions

What is CVE-2026-89485?
In the Linux kernel, the following vulnerability has been resolved: lockd: pin next file across nlm_inspect_file lock-drop nlm_traverse_files() pins the current file with f_count++ across a mutex_unlock for nlm_inspect_file(), but nothing pins the saved next pointer. A concurrent nlm_release_file() can kfree the next file during the unlock window, and the iterator dereferences freed memory on the next loop step. Pin both current and next before the lock-drop. Advance by swapping the pinned cursors at the end of each iteration so next is always held alive across the unlock. Always call nlm_file_release() after dropping the iteration pin, regardless of whether the file matched the predicate. Use nlm_file_inuse(), which does a live walk of the inode lock list, rather than the cached f_locks field, so skipped files that never ran nlm_inspect_file() are evaluated correctly. Because every file in a hash bucket is now pinned and released, files skipped by the is_failover_file predicate that have no locks, blocks, shares, or external references are deleted during traversal. The old code never evaluated skipped files for cleanup. The new behavior is intentional: such files are stale and should not persist in the table.
How severe is CVE-2026-89485?
CVE-2026-89485 has a CVSS score of 9.8/10 (CRITICAL severity). The EPSS model estimates a 0.63% probability of exploitation in the next 30 days.
How do I fix CVE-2026-89485?
Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

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Source: NVD / NIST