CVE-2026-63800

CriticalCVSS 9.8

Published: 19/07/2026(UTC)Updated: 29/07/2026(UTC)Translated: 21/07/2026(UTC)NVD NIST

Exploitation Probability (EPSS)

Low risk

0.50%

40th percentile - higher than 40% of all known CVEs

Summary

A use-after-free vulnerability was found in the Linux kernel's pnfs_update_layout() function in the pNFS implementation. The issue occurs when the NFS_LAYOUT_RETURN branch calls pnfs_put_layout_hdr(lo) before the tracepoint trace_pnfs_update_layout(), which still references the freed 'lo' structure.

Risk Assessment

This vulnerability can lead to undefined kernel behavior, including potential arbitrary code execution by a local attacker, compromising system confidentiality, integrity, and availability.

Recommendation

Immediately update the Linux kernel to a version containing the fix that moves the tracepoint call before pnfs_put_layout_hdr(lo).

Original NVD description (English source)

In the Linux kernel, the following vulnerability has been resolved: pNFS: Fix use-after-free in pnfs_update_layout() When hitting the NFS_LAYOUT_RETURN branch in pnfs_update_layout(), the code calls pnfs_prepare_to_retry_layoutget(lo). If it succeeds, pnfs_put_layout_hdr(lo) is called before trace_pnfs_update_layout(), which still references 'lo'. This results in a use-after-free when the tracepoint accesses lo's fields. Fix this by moving the tracepoint call before pnfs_put_layout_hdr(lo).