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VulnerabilityPublished Updated

CVE-2026-31674: Linux kernel · netfilter: ip6t_rt: reject oversized addrnr in rt_mt6_check()

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.1 High · fixed in ded71f5684df16fa645cca5bf4fe6b0cd8a46119 : patch Linux kernel soon.

Data as of 26 Oct 2026, 17:30 UTC

CVSS 3.1 base score
7.1High
How severe the flaw is on the 0–10 CVSS scale.
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.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in ded71f5684df16fa645cca5bf4fe6b0cd8a46119, d8795fde1f78669a87c87ac29fceab2f104daa8c, c6a503a9f4debc654e3a6a7ca1f7fce6a9953c59 +5
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 25 Apr 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq 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

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < ded71f5684df16fa645cca5bf4fe6b0cd8a46119
Fixed in
  • ded71f5684df16fa645cca5bf4fe6b0cd8a46119
LinuxLinuxAffected
  • ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < d8795fde1f78669a87c87ac29fceab2f104daa8c
Fixed in
  • d8795fde1f78669a87c87ac29fceab2f104daa8c
LinuxLinuxAffected
  • ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < c6a503a9f4debc654e3a6a7ca1f7fce6a9953c59
Fixed in
  • c6a503a9f4debc654e3a6a7ca1f7fce6a9953c59
LinuxLinuxAffected
  • ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < af9b7e2b765966457f4ec23be5bd34a141f89574
Fixed in
  • af9b7e2b765966457f4ec23be5bd34a141f89574
LinuxLinuxAffected
  • ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < a28ebf6f99de270d6338ccdc3b49f3e818f99b7b
Fixed in
  • a28ebf6f99de270d6338ccdc3b49f3e818f99b7b
LinuxLinuxAffected
  • ≥ 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2, < 29ea965a1353bc8303877422f79c8211e9ba9c55
Fixed in
  • 29ea965a1353bc8303877422f79c8211e9ba9c55

AI-suggested

A fix is available and has been applied in the Linux kernel. Users should update to a fixed kernel version that includes the patches identified by the commit hashes provided in the established facts. Since this is a kernel-level vulnerability, applying the official kernel updates from the Linux vendor or distribution is the recommended remediation. No additional mitigations are indicated by the vendor advisory.

Description

CVE-2026-31674 is a high-severity vulnerability in the Linux kernel's netfilter subsystem, specifically in the ip6t_rt module. The flaw involves improper validation of the addrnr parameter in the rt_mt6_check() function, which can lead to out-of-bounds access. This vulnerability has been addressed by rejecting rules where addrnr exceeds the allowed IP6T_RT_HOPS limit during rule installation, preventing malformed rules from causing memory safety issues.

References

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