CVE-2026-89783: Linux kernel · xfrm6: fix out-of-bounds write in xfrm6_input_addr() when secpath is full
Affects Linux kernelSource GCVE Database
Not known to be exploited · CVSS 9.8 Critical.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.7% chance of exploitation in 30 days – higher than 53% 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 16 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 boundary check in the Linux kernel's xfrm6_input_addr() function. Users should apply the updated kernel versions that include this patch. Since this is a kernel-level vulnerability, upgrading to a patched kernel release is the recommended remediation.
Description
A vulnerability in the Linux kernel's xfrm6_input_addr() function allows an out-of-bounds write when the security path (secpath) is full. This occurs due to an off-by-one error in the depth check, leading to a write beyond the allocated array boundary. The issue affects specific Linux kernel versions and has been resolved by correcting the boundary check condition.
References
- ubuntu.com/security/CVE-2026-89783 (opens in a new tab)
- cve.org/CVERecord?id=CVE-2026-89783 (opens in a new tab)
- git.kernel.org/linus/5d9e3bf34fec9a5d237e4b7cef4a707bc2e091bc (opens in a new tab)
- git.kernel.org/stable/c/0f679e0523ddfff3fb554336ceb874b0e51e9cd3 (opens in a new tab)
- git.kernel.org/stable/c/48996649222e95008cdb98cd58579e3fc8e5ee06 (opens in a new tab)
- git.kernel.org/stable/c/5d9e3bf34fec9a5d237e4b7cef4a707bc2e091bc (opens in a new tab)
- git.kernel.org/stable/c/5f35a29a5eed3d80befd32050843ac88dea3d61a (opens in a new tab)
- git.kernel.org/stable/c/68e8737fe8e72f085c608cff322b3d2de8340af1 (opens in a new tab)
- git.kernel.org/stable/c/8fe2c53fb81f5ad5be43af2ad09583f7c78b4b77 (opens in a new tab)
- git.kernel.org/stable/c/91fc387f63c00ddfb5221127a17bac97549a8343 (opens in a new tab)
- git.kernel.org/stable/c/bdcda866c89f9a8b1acdabf02d26cde9fbe501d8 (opens in a new tab)
- msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-89783.json (opens in a new tab)
- support.microsoft.com/lifecycle (opens in a new tab)
- first.org/cvss (opens in a new tab)