CVE-2026-23204

Kernel-memory disclosure and crash via negative offset

Published Feb 14, 2026 · Updated Feb 14, 2026

Out-of-bounds read in the cls_u32 classifier in Linux Kernel allows local users to disclose kernel memory or crash the system. In u32_classify, skb_header_pointer accepts a crafted negative offset and reads before the intended packet-data boundary. Exploitation requires local low-privileged access and a crafted cls_u32 classification path; the read exposes kernel memory or triggers a kernel crash.

CVSS severity7.1
High
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

Out-of-bounds read in the cls_u32 classifier in Linux Kernel allows local users to disclose kernel memory or crash the system. In u32_classify, skb_header_pointer accepts a crafted negative offset and reads before the intended packet-data boundary. Exploitation requires local low-privileged access and a crafted cls_u32 classification path; the read exposes kernel memory or triggers a kernel crash.

The record

CVE
CVE-2026-23204
Published
Feb 14, 2026
Updated
Feb 14, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-125
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 14, 2026CVE publishedPublication date reported by the CVE source.
  2. Feb 14, 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=2.6.35
  2. Affected versionversion=fbc2e7d9cf49e0bf89b9e91fd60a06851a855c5d <13336a6239b9d7c6e61483017bb8bdfe3ceb10a5
  3. Affected versionversion=fbc2e7d9cf49e0bf89b9e91fd60a06851a855c5d <8a672f177ebe19c93d795fbe967846084fbc7943
  4. Affected versionversion=fbc2e7d9cf49e0bf89b9e91fd60a06851a855c5d <cabd1a976375780dabab888784e356f574bbaed8
  5. Affected versionversion=fbc2e7d9cf49e0bf89b9e91fd60a06851a855c5d <e41a23e61259f5526af875c3b86b3d42a9bae0e5

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=2.6.35; version=fbc2e7d9cf49e0bf89b9e91fd60a06851a855c5d <13336a6239b9d7c6e61483017bb8bdfe3ceb10a5; version=fbc2e7d9cf49e0bf89b9e91fd60a06851a855c5d <8a672f177ebe19c93d795fbe967846084fbc7943; version=fbc2e7d9cf49e0bf89b9e91fd60a06851a855c5d <cabd1a976375780dabab888784e356f574bbaed8; version=fbc2e7d9cf49e0bf89b9e91fd60a06851a855c5d <e41a23e61259f5526af875c3b86b3d42a9bae0e5

Published CVSS scores

7.1kernel.orgCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/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

CWE-125Out-of-bounds Read

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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