CVE-2026-23270

Local kernel compromise via act_ct use-after-free

Published Mar 18, 2026 · Updated Mar 18, 2026

Use-after-free in Linux Kernel net/sched allows local users to gain kernel privileges through an act_ct egress filter configuration. A non-clsact egress qdisc fails to honor TC_ACT_CONSUMED after act_ct leaves the skb with the defragmentation engine, so later access reuses freed packet memory. Exploitation requires CAP_NET_ADMIN, obtainable through enabled user namespaces, and permits kernel memory access, code execution, or a kernel crash.

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

Use-after-free in Linux Kernel net/sched allows local users to gain kernel privileges through an act_ct egress filter configuration. A non-clsact egress qdisc fails to honor TC_ACT_CONSUMED after act_ct leaves the skb with the defragmentation engine, so later access reuses freed packet memory. Exploitation requires CAP_NET_ADMIN, obtainable through enabled user namespaces, and permits kernel memory access, code execution, or a kernel crash.

The record

CVE
CVE-2026-23270
Published
Mar 18, 2026
Updated
Mar 18, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-416, T1068
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Mar 18, 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=0b5b831122fc3789fff75be433ba3e4dd7b779d4
  2. Affected versionversion=172ba7d46c202e679f3ccb10264c67416aaeb1c4
  3. Affected versionversion=3f14b377d01d8357eba032b4cabc8c1149b458b6 <11cb63b0d1a0685e0831ae3c77223e002ef18189
  4. Affected versionversion=3f14b377d01d8357eba032b4cabc8c1149b458b6 <380ad8b7c65ea7aa10ef2258297079ed5ac1f5b6
  5. Affected versionversion=3f14b377d01d8357eba032b4cabc8c1149b458b6 <524ce8b4ea8f64900b6c52b6a28df74f6bc0801e
  6. Affected versionversion=3f14b377d01d8357eba032b4cabc8c1149b458b6 <9deda0fcda5c1f388c5e279541850b71a2ccfcf4
  7. Affected versionversion=6.8
  8. Affected versionversion=73f7da5fd124f2cda9161e2e46114915e6e82e97
  9. Affected versionversion=f5346df0591d10bc948761ca854b1fae6d2ef441

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=0b5b831122fc3789fff75be433ba3e4dd7b779d4; version=172ba7d46c202e679f3ccb10264c67416aaeb1c4; version=3f14b377d01d8357eba032b4cabc8c1149b458b6 <11cb63b0d1a0685e0831ae3c77223e002ef18189; version=3f14b377d01d8357eba032b4cabc8c1149b458b6 <380ad8b7c65ea7aa10ef2258297079ed5ac1f5b6; version=3f14b377d01d8357eba032b4cabc8c1149b458b6 <524ce8b4ea8f64900b6c52b6a28df74f6bc0801e; version=3f14b377d01d8357eba032b4cabc8c1149b458b6 <9deda0fcda5c1f388c5e279541850b71a2ccfcf4; version=6.8; version=73f7da5fd124f2cda9161e2e46114915e6e82e97; version=f5346df0591d10bc948761ca854b1fae6d2ef441

Published CVSS scores

7.8UbuntuCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.8Linux Kernel CVE TeamCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
7.0Oracle LinuxCVSS:3.1/AV:L/AC:H/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

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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-416Use After Free
T1068Exploitation for Privilege Escalation

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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