CVE-2026-31414

Service interruption via unreferenced conntrack helper access

Published Apr 13, 2026 · Updated Apr 13, 2026

Unsafe object access in Linux Kernel netfilter allows attackers to interrupt service through unreferenced conntrack helper access. The ctnetlink and /proc dump paths call nfct_help() without retaining a reference to the master conntrack, making helper-name access unsafe. Published assessments disagree on reachability: kernel.org scores unauthenticated network access, while Ubuntu's CVSS v4 assessment requires local low-privileged access and additional conditions.

CVSS severity9.8
Critical
EPSS probability0.40%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Unsafe object access in Linux Kernel netfilter allows attackers to interrupt service through unreferenced conntrack helper access. The ctnetlink and /proc dump paths call nfct_help() without retaining a reference to the master conntrack, making helper-name access unsafe. Published assessments disagree on reachability: kernel.org scores unauthenticated network access, while Ubuntu's CVSS v4 assessment requires local low-privileged access and additional conditions.

The record

CVE
CVE-2026-31414
Published
Apr 13, 2026
Updated
Apr 13, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
Unavailable
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Apr 13, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 13, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3dfd3f7712b5a800f2ba632179e9b738076a51f0
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <4bd1b3d839172724b33d8d02c5a4ff6a1c775417
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <847cb7fe26c5ce5dce0d1a41fac1ea488b7f1781
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b53294bff19e56ada2f230ceb8b1ffde61cc3817
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e7ccaa0a62a8ff2be5d521299ce79390c318d306
  6. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f01794106042ee27e54af6fdf5b319a2fe3df94d

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <3dfd3f7712b5a800f2ba632179e9b738076a51f0; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <4bd1b3d839172724b33d8d02c5a4ff6a1c775417; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <847cb7fe26c5ce5dce0d1a41fac1ea488b7f1781; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <b53294bff19e56ada2f230ceb8b1ffde61cc3817; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <e7ccaa0a62a8ff2be5d521299ce79390c318d306; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f01794106042ee27e54af6fdf5b319a2fe3df94d

Published CVSS scores

9.8kernel.orgCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
7.3UbuntuCVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
5.8Amazon LinuxCVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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