CVE-2026-23209

Kernel privilege escalation via macvlan use-after-free

Published Feb 14, 2026 · Updated Feb 14, 2026

Use-after-free in the macvlan driver in affected Linux Kernel releases allows local users to execute code with kernel privileges. A failed macvlan_common_newlink registration frees a net_device without removing its vlan_source_hash entry, leaving macvlan_forward_source to dereference it. A local user can obtain CAP_NET_ADMIN through a user namespace, create the failing source-mode link, and send a matching packet to cause kernel code execution or a panic.

CVSS severity7.8
High
EPSS probability0.12%
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 the macvlan driver in affected Linux Kernel releases allows local users to execute code with kernel privileges. A failed macvlan_common_newlink registration frees a net_device without removing its vlan_source_hash entry, leaving macvlan_forward_source to dereference it. A local user can obtain CAP_NET_ADMIN through a user namespace, create the failing source-mode link, and send a matching packet to cause kernel code execution or a panic.

The record

CVE
CVE-2026-23209
Published
Feb 14, 2026
Updated
Feb 14, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-416, T1068
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

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=4.9
  2. Affected versionversion=aa5fd0fb77486b8a6764ead8627baa14790e4280 <11ba9f0dc865136174cb98834280fb21bbc950c7
  3. Affected versionversion=aa5fd0fb77486b8a6764ead8627baa14790e4280 <5dae6b36a7cb7a4fcf4121b95e9ca7f96f816c8a
  4. Affected versionversion=aa5fd0fb77486b8a6764ead8627baa14790e4280 <986967a162142710076782d5b93daab93a892980
  5. Affected versionversion=aa5fd0fb77486b8a6764ead8627baa14790e4280 <c43d0e787cbba569ec9d11579ed370b50fab6c9c
  6. Affected versionversion=aa5fd0fb77486b8a6764ead8627baa14790e4280 <cdedcd5aa3f3cb8b7ae0f87ab3a936d0bd583d66
  7. Affected versionversion=aa5fd0fb77486b8a6764ead8627baa14790e4280 <da5c6b8ae47e414be47e5e04def15b25d5c962dc
  8. Affected versionversion=aa5fd0fb77486b8a6764ead8627baa14790e4280 <f8db6475a83649689c087a8f52486fcc53e627e9

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=4.9; version=aa5fd0fb77486b8a6764ead8627baa14790e4280 <11ba9f0dc865136174cb98834280fb21bbc950c7; version=aa5fd0fb77486b8a6764ead8627baa14790e4280 <5dae6b36a7cb7a4fcf4121b95e9ca7f96f816c8a; version=aa5fd0fb77486b8a6764ead8627baa14790e4280 <986967a162142710076782d5b93daab93a892980; version=aa5fd0fb77486b8a6764ead8627baa14790e4280 <c43d0e787cbba569ec9d11579ed370b50fab6c9c; version=aa5fd0fb77486b8a6764ead8627baa14790e4280 <cdedcd5aa3f3cb8b7ae0f87ab3a936d0bd583d66; version=aa5fd0fb77486b8a6764ead8627baa14790e4280 <da5c6b8ae47e414be47e5e04def15b25d5c962dc; version=aa5fd0fb77486b8a6764ead8627baa14790e4280 <f8db6475a83649689c087a8f52486fcc53e627e9

Published CVSS scores

7.8kernel.orgCVSS: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 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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