CVE-2026-89675: Linux kernel · nfsd: fix UAF in async copy cancel and shutdown
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 9.8 Critical.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.4% chance of exploitation in 30 days – higher than 38% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
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 11 Sep 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
Affected software
| Product | Affected | Fixed in |
|---|---|---|
Ubuntu 26.04 LTSlinuxpkg:deb/ubuntu/linux?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-awspkg:deb/ubuntu/linux-aws?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azurepkg:deb/ubuntu/linux-azure?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-azure-fdepkg:deb/ubuntu/linux-azure-fde?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gcppkg:deb/ubuntu/linux-gcp?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Ubuntu 26.04 LTSlinux-gkepkg:deb/ubuntu/linux-gke?arch=source&distro=resoluteOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
A fix is available that corrects the async copy teardown lifetime management, reference counting, and task pinning in the Linux kernel nfsd component. Users should apply the official kernel updates corresponding to their affected versions to remediate this vulnerability. No additional mitigation steps are indicated beyond applying the patch.
Description
A use-after-free (UAF) vulnerability in the Linux kernel's NFS daemon (nfsd) async copy handling was resolved. The flaw involved race conditions during async copy cancellation and shutdown, leading to potential use of freed memory and task_struct dereferencing after free. This could cause system instability or crashes. The fix improves reference counting, locking, and task pinning to ensure safe teardown of async copies.
References
- nvd.nist.gov/vuln/detail/CVE-2026-89675 (opens in a new tab)
- git.kernel.org/stable/c/62c0f6eaf050bb9284c1f9cac6ed1770092e6b95 (opens in a new tab)
- git.kernel.org/stable/c/9031493ef7369d5c59c4bacc96f0c85965f09a98 (opens in a new tab)
- git.kernel.org/stable/c/a385cf5e016b748babf94cc664e43a26e17db117 (opens in a new tab)
- ubuntu.com/security/CVE-2026-89675 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-89675 (opens in a new tab)
- git.kernel.org/linus/62c0f6eaf050bb9284c1f9cac6ed1770092e6b95 (opens in a new tab)