CVE-2026-89545: Linux kernel · sunrpc: defer rq_argp and rq_resp free until after RCU grace period
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High.
Data as of 27 Oct 2026, 05:11 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 5% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CVSS:3.1/AV:L/AC:L/PR:L/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 defers freeing rq_argp and rq_resp until after the RCU grace period via call_rcu() callbacks. Users should apply the updated Linux kernel versions that include this patch to mitigate the vulnerability.
Description
A use-after-free vulnerability in the Linux kernel's sunrpc subsystem was resolved by deferring the freeing of rq_argp and rq_resp until after the RCU grace period. The flaw allowed RCU readers to access freed memory, potentially causing system instability or security issues. The fix moves the freeing of these resources into an explicit call_rcu() callback alongside the struct free.
References
- nvd.nist.gov/vuln/detail/CVE-2026-89545 (opens in a new tab)
- git.kernel.org/stable/c/08bc49e0541260bf294962cf889a32a2d2713ad6 (opens in a new tab)
- git.kernel.org/stable/c/c479bde671cbe2f9e152834a8b0eb7c3c295bbaf (opens in a new tab)
- git.kernel.org/stable/c/e0c5693d3f9a5d4911735ab0e0eba4eecb1f1090 (opens in a new tab)
- ubuntu.com/security/CVE-2026-89545 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-89545 (opens in a new tab)
- git.kernel.org/linus/c479bde671cbe2f9e152834a8b0eb7c3c295bbaf (opens in a new tab)