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CVE-2026-63800: pNFS: Fix use-after-free in pnfs_update_layout()

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.6% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2026-07-19 · updated 2026-10-19
• Weakness: CWE-416

Description

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 kernel: from 5.4.91 before 5.5; from 5.10.9 before 5.10.260; from 5.11.1 before 5.15.211; from 5.16 before 6.1.177; from 6.2 before 6.6.144; from 6.7 before 6.12.95 — fixed in 5.10.260, 5.15.211, 5.5, 6.1.177, 6.12.95, 6.18.38

How to fix

Upgrade to a fixed version: Linux kernel 5.10.260, 5.15.211, 5.5, 6.1.177. Check the vendor advisory for mitigations.

References

• https://git.kernel.org/stable/c/13e198a90ca4050f4bee8a3f23680389a6563ccc
• https://git.kernel.org/stable/c/1f24b8302c77dcaf79c64c073877a3b9f4dd25d2
• https://git.kernel.org/stable/c/200e7637f4d6a1342987045eea72641524f909dc
• https://git.kernel.org/stable/c/2883ddd7542b4437a2ab4908fe2773f690e20889
• https://git.kernel.org/stable/c/4ad8b9a85dbf57ca532ee9e65ad7e6498bfbbf98
• https://git.kernel.org/stable/c/7e37e9b3e82ade881e1798e2f4fcc54aff7793c1
• https://git.kernel.org/stable/c/9645aaf689aff57427ece3b9fa47d5b5399417f4
• https://git.kernel.org/stable/c/9c0fb5c09ae5bd68dc0038692af8127029cb0385

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