Linux KernelOperating system · Linux
CVE-2026-31414
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedIn the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_expect: use expect->helper Use expect->helper in ctnetlink and /proc to dump the helper name. Using nfct_help() without holding a reference to the master conntrack is unsafe. Use exp->master->helper in ctnetlink path if userspace does not provide an explicit helper when creating an expectation to retain the existing behaviour. The ctnetlink expectation path holds the reference on the master conntrack and nf_conntrack_expect lock and the nfnetlink glue path refers to the master ct that is attached to the skb.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceThe Linux kernel's netfilter nf_conntrack_expect module has a memory safety vulnerability where using nfct_help() to access helper information without holding a reference to the master conntrack is unsafe, potentially leading to use-after-free or race conditions when dumping helper names via ctnetlink or /proc interfaces.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
Linux KernelOperating system
>= 2.6.30, < 6.1.168>= 6.2, < 6.6.134>= 6.7, < 6.12.81>= 6.13, < 6.18.22>= 6.19, < 6.19.12= 7.0CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
-
Check kernel versionRun `uname -r` or `cat /proc/version` to get the running kernel versionAffected if The kernel version falls within any of these ranges: >= 2.6.30 and < 6.1.168; >= 6.2 and < 6.6.134; >= 6.7 and < 6.12.81; >= 6.13 and < 6.18.22; >= 6.19 and < 6.19.12; or is exactly 7.0. If your version is not in any of these ranges, you are likely not affected.
-
Verify netfilter conntrack is activeCheck if nf_conntrack module is loaded with `lsmod | grep nf_conntrack` or check /proc/net/nf_conntrack for active connectionsAffected if If conntrack is not loaded or not in use, the vulnerability cannot be triggered since the flaw is in the nf_conntrack_expect code path.
-
Check for loaded conntrack helpersList loaded helper modules with `lsmod | grep nf_conntrack_helper` or check /proc/net/nf_conntrack_expect to see if expectation handling is activeAffected if The vulnerability involves unsafe access to conntrack helpers via nfct_help() without proper reference holding. If no helpers are loaded and no expectations are being created, exploitation is not possible.
-
Inspect active conntrack expectationsView /proc/net/nf_conntrack_expect if it exists and contains entries, particularly looking for expectations that reference helpersAffected if If the file shows active expectations that involve helper assignment (visible in the expectation data), the vulnerable code path may be exercised when userspace creates expectations without explicitly providing a helper.
You are affected if your kernel version is in the affected ranges AND the netfilter conntrack subsystem with expectation handling is actively in use on your system.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped6.1.1686.6.1346.12.81
Apply the upstream kernel patch that replaces nfct_help() calls with direct expect->helper references and ensures proper reference handling on the master conntrack before accessing helper information.
Upgrade to kernel version 6.1.168 or later (for 6.1.y branch), 6.6.134 or later (for 6.2-6.6.y branch), 6.12.81 or later (for 6.7-6.12.y branch), or 6.18.22 or later (for 6.13-6.18.y branch)
- 1. Identify the currently running Linux kernel version using 'uname -r'
- 2. Check if the running version falls within any of the affected ranges: >= 2.6.30 and < 6.1.168, >= 6.2 and < 6.6.134, >= 6.7 and < 6.12.81, or >= 6.13 and < 6.18.22
- 3. Schedule a maintenance window for kernel upgrade (requires system reboot)
- 4. Update the system package manager and install a kernel version equal to or higher than the first fixed version for your branch: 6.1.168, 6.6.134, 6.12.81, or 6.18.22
- 5. After installation, reboot the system to load the new kernel
- 6. Verify the new kernel version is running using 'uname -r' and confirm it is not in any affected range
Generated from the published advisory — verify against the referenced sources before acting.
Fix this in Linux Kernel
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing16.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $8,576.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-31414 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-31414 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data