CVE-2026-89540: Linux kernel · sunrpc: init gssp_lock before publishing proc entry
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 7.8 High.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.1% chance of exploitation in 30 days – higher than 2% 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 initializes the gssp_lock mutex earlier in the network namespace initialization process, eliminating the race window. Users should apply the official kernel updates that include this fix. Since this is a kernel-level vulnerability, upgrading to a patched kernel version is the recommended remediation.
Description
A race condition vulnerability in the Linux kernel's sunrpc module was resolved by initializing a mutex lock before publishing a proc entry. The flaw allowed a window where a write operation could lock an uninitialized mutex, potentially causing concurrent access issues and resource leaks. This was fixed by moving the mutex initialization to an earlier point in the network namespace lifecycle.
References
- nvd.nist.gov/vuln/detail/CVE-2026-89540 (opens in a new tab)
- git.kernel.org/stable/c/3f019571928b269feebcff59926ec13294215e0e (opens in a new tab)
- git.kernel.org/stable/c/5ce1ed6159731a41fdd0b03eedbed4e147036a5a (opens in a new tab)
- git.kernel.org/stable/c/edeefb111d6181a4aa278f415b005efe284b9489 (opens in a new tab)
- git.kernel.org/stable/c/f15b87521168c2a92cb1931f532cba422f856f01 (opens in a new tab)
- ubuntu.com/security/CVE-2026-89540 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-89540 (opens in a new tab)
- git.kernel.org/linus/5ce1ed6159731a41fdd0b03eedbed4e147036a5a (opens in a new tab)
- msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-89540.json (opens in a new tab)
- support.microsoft.com/lifecycle (opens in a new tab)
- first.org/cvss (opens in a new tab)