CVE-2026-23391

Kernel compromise via stale xt_CT template references

Published Mar 25, 2026 · Updated Mar 25, 2026

Dangling-reference access in Linux Kernel 3.4 and later allows local users to access kernel memory, alter kernel state, or crash the system. When an xt_CT rule carrying a connection-tracking helper or timeout policy is removed, xt_ct_tg_destroy releases the referenced object without first dropping packets that still hold its template in an nfqueue. Exploitation requires local low-privileged access and a queued packet retaining the removed template; zone and event-cache templates only copy values and are unaffected.

CVSS severity7.8
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

Dangling-reference access in Linux Kernel 3.4 and later allows local users to access kernel memory, alter kernel state, or crash the system. When an xt_CT rule carrying a connection-tracking helper or timeout policy is removed, xt_ct_tg_destroy releases the referenced object without first dropping packets that still hold its template in an nfqueue. Exploitation requires local low-privileged access and a queued packet retaining the removed template; zone and event-cache templates only copy values and are unaffected.

The record

CVE
CVE-2026-23391
Published
Mar 25, 2026
Updated
Mar 25, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 25, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 25, 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=24de58f465165298aaa8f286b2592f0163706cfe <19a230dec6bb8928e3f96387f9085cf2c79bcef9
  2. Affected versionversion=24de58f465165298aaa8f286b2592f0163706cfe <63b8097cea1923fe82cd598068d0796da8c015ec
  3. Affected versionversion=24de58f465165298aaa8f286b2592f0163706cfe <777d02efe3d630cca4c1b63962cec17c57711325
  4. Affected versionversion=24de58f465165298aaa8f286b2592f0163706cfe <cb549925875fa06dd155e49db4ac2c5044c30f9c
  5. Affected versionversion=24de58f465165298aaa8f286b2592f0163706cfe <d2d0bae0c9a2a17b6990a2966f5cdce0813d6256
  6. Affected versionversion=24de58f465165298aaa8f286b2592f0163706cfe <f62a218a946b19bb59abdd5361da85fa4606b96b
  7. Affected versionversion=3.4

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=24de58f465165298aaa8f286b2592f0163706cfe <19a230dec6bb8928e3f96387f9085cf2c79bcef9; version=24de58f465165298aaa8f286b2592f0163706cfe <63b8097cea1923fe82cd598068d0796da8c015ec; version=24de58f465165298aaa8f286b2592f0163706cfe <777d02efe3d630cca4c1b63962cec17c57711325; version=24de58f465165298aaa8f286b2592f0163706cfe <cb549925875fa06dd155e49db4ac2c5044c30f9c; version=24de58f465165298aaa8f286b2592f0163706cfe <d2d0bae0c9a2a17b6990a2966f5cdce0813d6256; version=24de58f465165298aaa8f286b2592f0163706cfe <f62a218a946b19bb59abdd5361da85fa4606b96b; version=3.4

Published CVSS scores

7.8LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/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 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1068Exploitation for Privilege Escalation

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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