CVE-2026-63800: Linux Kernel

Critical severity, CVSS 9.8. EPSS: 0.5% chance of exploitation in the next 30 days.

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).

Affected products

• Linux Linux Kernel: from 5.4.91, before 5.5 (fixed in 5.5); from 5.10.9, before 5.10.260 (fixed in 5.10.260); from 5.11.1, before 5.15.211 (fixed in 5.15.211); from 5.16, before 6.1.177 (fixed in 6.1.177); from 6.2, before 6.6.144 (fixed in 6.6.144); from 6.7, before 6.12.95 (fixed in 6.12.95); …

Published 2026-07-19. Last modified 2026-08-17.