CVE-2026-31414: Linux kernel · netfilter: nf_conntrack_expect: use expect->helper
Affects Linux kernelSource CVE Database V5
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
- 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:HExploitation evidence
Disclosed: evidence found.
CVE published 13 Apr 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
Upgrade to a fixed release listed under Affected software.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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| LinuxLinux | Affected
| Fixed in
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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
- git.kernel.org/stable/c/847cb7fe26c5ce5dce0d1a41fac1ea488b7f1781 (opens in a new tab)
- git.kernel.org/stable/c/e7ccaa0a62a8ff2be5d521299ce79390c318d306 (opens in a new tab)
- git.kernel.org/stable/c/4bd1b3d839172724b33d8d02c5a4ff6a1c775417 (opens in a new tab)
- git.kernel.org/stable/c/b53294bff19e56ada2f230ceb8b1ffde61cc3817 (opens in a new tab)
- git.kernel.org/stable/c/3dfd3f7712b5a800f2ba632179e9b738076a51f0 (opens in a new tab)
- git.kernel.org/stable/c/f01794106042ee27e54af6fdf5b319a2fe3df94d (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-082556.html (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-019113.html (opens in a new tab)
- cert-portal.siemens.com/productcert/html/ssa-457936.html (opens in a new tab)