CVE-2026-63800: Linux kernel · pNFS: Fix use-after-free in pnfs_update_layout()
Source GCVE Database
Not known to be exploited · CVSS 9.8 Critical · fixed in 9645aaf689aff57427ece3b9fa47d5b5399417f4 : patch Linux kernel as a priority.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.6% chance of exploitation in 30 days – higher than 50% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 9645aaf689aff57427ece3b9fa47d5b5399417f4, 2883ddd7542b4437a2ab4908fe2773f690e20889, 200e7637f4d6a1342987045eea72641524f909dc +7
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:HExploitation evidence
Disclosed: evidence found.
CVE published 19 Jul 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
|
| LinuxLinux | Affected
| Fixed in– |
AI-suggested
A fix for this vulnerability has been implemented in the Linux kernel by reordering the tracepoint call to occur before the object is freed. Users should apply the official kernel updates that include this fix. Patch status is not explicitly confirmed in the provided data; therefore, check the vendor or kernel maintainers' advisories for the specific patched versions and apply updates accordingly.
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).
References
- nvd.nist.gov/vuln/detail/CVE-2026-63800 (opens in a new tab)
- git.kernel.org/stable/c/13e198a90ca4050f4bee8a3f23680389a6563ccc (opens in a new tab)
- git.kernel.org/stable/c/1f24b8302c77dcaf79c64c073877a3b9f4dd25d2 (opens in a new tab)
- git.kernel.org/stable/c/200e7637f4d6a1342987045eea72641524f909dc (opens in a new tab)
- git.kernel.org/stable/c/2883ddd7542b4437a2ab4908fe2773f690e20889 (opens in a new tab)
- git.kernel.org/stable/c/4ad8b9a85dbf57ca532ee9e65ad7e6498bfbbf98 (opens in a new tab)
- git.kernel.org/stable/c/7e37e9b3e82ade881e1798e2f4fcc54aff7793c1 (opens in a new tab)
- git.kernel.org/stable/c/9645aaf689aff57427ece3b9fa47d5b5399417f4 (opens in a new tab)
- git.kernel.org/stable/c/9c0fb5c09ae5bd68dc0038692af8127029cb0385 (opens in a new tab)