CVE-2026-31495

Kernel service interruption via unchecked shift count

Published Apr 22, 2026 · Updated Apr 22, 2026

Improper input validation in Linux Kernel ctnetlink allows local users to interrupt service through malformed netlink attributes. The ctnetlink path accepts TCP window-scale values from 0 through 255 and later uses them as a 32-bit shift count, although valid values end at 14. Local low-privilege access is required, and the published impact is limited to availability with no confidentiality or integrity loss.

CVSS severity5.5
Medium
EPSS probability0.13%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Improper input validation in Linux Kernel ctnetlink allows local users to interrupt service through malformed netlink attributes. The ctnetlink path accepts TCP window-scale values from 0 through 255 and later uses them as a 32-bit shift count, although valid values end at 14. Local low-privilege access is required, and the published impact is limited to availability with no confidentiality or integrity loss.

The record

CVE
CVE-2026-31495
Published
Apr 22, 2026
Updated
Apr 22, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1499.004
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Apr 22, 2026CVE publishedPublication date reported by the CVE source.
  2. Apr 22, 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=2.6.22
  2. Affected versionversion=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <2ef71307c86a9f866d6e28f1a0c06e2e9d794474
  3. Affected versionversion=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <435b576cd2faa75154777868f8cbb73bf71644d3
  4. Affected versionversion=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <45c33e79ae705b7af97e3117672b6cd258dd0b1b
  5. Affected versionversion=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <4f7d25f3f0786402ba48ff7d13b6241d77d975f5
  6. Affected versionversion=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <675c913b940488a84effdeeac5a1cfb657b59804
  7. Affected versionversion=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <8f15b5071b4548b0aafc03b366eb45c9c6566704
  8. Affected versionversion=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <c6cb41eaae875501eaaa487b8db6539feb092292
  9. Affected versionversion=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <fcec5ce2d73a41668b24e3f18c803541602a59f6

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=2.6.22; version=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <2ef71307c86a9f866d6e28f1a0c06e2e9d794474; version=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <435b576cd2faa75154777868f8cbb73bf71644d3; version=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <45c33e79ae705b7af97e3117672b6cd258dd0b1b; version=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <4f7d25f3f0786402ba48ff7d13b6241d77d975f5; version=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <675c913b940488a84effdeeac5a1cfb657b59804; version=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <8f15b5071b4548b0aafc03b366eb45c9c6566704; version=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <c6cb41eaae875501eaaa487b8db6539feb092292; version=c8e2078cfe414a99cf6f2f2f1d78c7e75392e9d4 <fcec5ce2d73a41668b24e3f18c803541602a59f6

Published CVSS scores

5.5NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/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)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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Your stack

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