CVE-2026-89604: Linux kernel · efivarfs: Rate limit statfs() handler
Affects Linux kernelSource GCVE Database
Not known to be exploited.
Data as of 26 Oct 2026, 12:55 UTC
Rated by Threat Radar · CVSS not yet scored by NVD
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 11% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Exploitation 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 rate limits the QueryVariableInfo() calls to twice per second and returns cached results for additional calls within that interval. Users should apply the updated Linux kernel versions that include this fix to mitigate the vulnerability.
Description
A vulnerability in the Linux kernel's efivarfs filesystem allows unprivileged users to cause a flood of costly QueryVariableInfo() calls by repeatedly invoking statfs() on the efivarfs mount point. This can disproportionately impact x86 systems where the variable store is backed by System Management Mode (SMM), as each call requires synchronization of all CPUs. The issue has been addressed by rate limiting these calls to twice per second and returning cached results for additional calls within that interval.
References
- nvd.nist.gov/vuln/detail/CVE-2026-89604 (opens in a new tab)
- git.kernel.org/stable/c/0dbc2e94b81df5a1264068b6ed3605c654b8afcb (opens in a new tab)
- git.kernel.org/stable/c/8953bdd1b9c0e748d5408d3d0b8e7aeee5c9cd41 (opens in a new tab)
- git.kernel.org/stable/c/92895a14329cc9533e2a74a265214f690ba3851a (opens in a new tab)
- git.kernel.org/stable/c/b2326338dc683e8c1067c0cbf7a47986c4190902 (opens in a new tab)
- msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-89604.json (opens in a new tab)
- support.microsoft.com/lifecycle (opens in a new tab)
- first.org/cvss (opens in a new tab)
- ubuntu.com/security/CVE-2026-89604 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-89604 (opens in a new tab)
- git.kernel.org/linus/b2326338dc683e8c1067c0cbf7a47986c4190902 (opens in a new tab)