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VulnerabilityPublished Updated

CVE-2026-31414: Linux kernel · netfilter: nf_conntrack_expect: use expect->helper

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 9.8 Critical · fixed in f01794106042ee27e54af6fdf5b319a2fe3df94d : patch Linux kernel as a priority.

Data as of 26 Oct 2026, 14:18 UTC

CVSS 3.1 base score
9.8Critical
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.5% chance of exploitation in 30 days – higher than 46% 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 can reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in f01794106042ee27e54af6fdf5b319a2fe3df94d, e7ccaa0a62a8ff2be5d521299ce79390c318d306, b53294bff19e56ada2f230ceb8b1ffde61cc3817 +3
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 13 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
  • ≥ ea781f197d6a835cbb93a0bf88ee1696296ed8aa, < f01794106042ee27e54af6fdf5b319a2fe3df94d
Fixed in
  • f01794106042ee27e54af6fdf5b319a2fe3df94d
LinuxLinuxAffected
  • ≥ ea781f197d6a835cbb93a0bf88ee1696296ed8aa, < e7ccaa0a62a8ff2be5d521299ce79390c318d306
Fixed in
  • e7ccaa0a62a8ff2be5d521299ce79390c318d306
LinuxLinuxAffected
  • ≥ ea781f197d6a835cbb93a0bf88ee1696296ed8aa, < b53294bff19e56ada2f230ceb8b1ffde61cc3817
Fixed in
  • b53294bff19e56ada2f230ceb8b1ffde61cc3817
LinuxLinuxAffected
  • ≥ ea781f197d6a835cbb93a0bf88ee1696296ed8aa, < 847cb7fe26c5ce5dce0d1a41fac1ea488b7f1781
Fixed in
  • 847cb7fe26c5ce5dce0d1a41fac1ea488b7f1781
LinuxLinuxAffected
  • ≥ ea781f197d6a835cbb93a0bf88ee1696296ed8aa, < 4bd1b3d839172724b33d8d02c5a4ff6a1c775417
Fixed in
  • 4bd1b3d839172724b33d8d02c5a4ff6a1c775417
LinuxLinuxAffected
  • ≥ ea781f197d6a835cbb93a0bf88ee1696296ed8aa, < 3dfd3f7712b5a800f2ba632179e9b738076a51f0
Fixed in
  • 3dfd3f7712b5a800f2ba632179e9b738076a51f0

AI-suggested

This vulnerability has been fixed in the Linux kernel. Users should update to a fixed kernel version containing the referenced commits (e.g., those identified by hashes f01794106042ee27e54af6fdf5b319a2fe3df94d and others). No additional mitigation is required beyond applying the official kernel patches.

Description

CVE-2026-31414 is a critical vulnerability in the Linux kernel's netfilter nf_conntrack_expect component. It involves unsafe use of nfct_help() without holding a reference to the master conntrack, which can lead to security issues. The flaw is addressed by properly using expect->helper in ctnetlink and /proc to safely dump the helper name and maintain reference integrity during expectation creation.

References

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