CVE-2026-89649: Linux kernel · ceph: bound xattr value length in __build_xattrs()
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 9.1 Critical.
Data as of 26 Oct 2026, 14:05 UTC
- EPSS
- 0.6% chance of exploitation in 30 days – higher than 52% 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:N/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 adds the missing bounds check in __build_xattrs() to prevent out-of-bounds reads. Users should apply the official Linux kernel patches that address CVE-2026-89649. Since this is a kernel vulnerability, updating to a patched kernel version is the recommended remediation. No additional mitigation is required once the patch is applied.
Description
A vulnerability in the Linux kernel's Ceph filesystem implementation allows a malicious metadata server to cause an out-of-bounds read during extended attribute (xattr) processing. Specifically, the final attribute's value length is not properly checked against the blob boundary, enabling disclosure of adjacent kernel heap memory to local users via getxattr(2) calls. This issue has been resolved by adding a missing bounds check that causes decoding to fail safely on malformed input.
References
- nvd.nist.gov/vuln/detail/CVE-2026-89649 (opens in a new tab)
- git.kernel.org/stable/c/1dd356310b1660215f9a3626580bf8b363ef981e (opens in a new tab)
- git.kernel.org/stable/c/38be2f3c41ecaba58bb92dc16603e09ba9fd64f1 (opens in a new tab)
- git.kernel.org/stable/c/68d541754d6cd3bb98d1fd8314f57e5eb533557d (opens in a new tab)
- git.kernel.org/stable/c/b12b3320c81fd72ab36388fb2445fec9c3038f10 (opens in a new tab)
- ubuntu.com/security/CVE-2026-89649 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-89649 (opens in a new tab)
- git.kernel.org/linus/68d541754d6cd3bb98d1fd8314f57e5eb533557d (opens in a new tab)