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VulnerabilityPublished Updated

CVE-2026-23209: Linux kernel · macvlan: fix error recovery in macvlan_common_newlink()

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High · fixed in f8db6475a83649689c087a8f52486fcc53e627e9 : patch Linux kernel soon.

Data as of 26 Oct 2026, 14:18 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.1% chance of exploitation in 30 days – higher than 7% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
CISA SSVC
Exploitation
No evidence of active exploitation and no public proof of concept
Automatable
Attackers cannot reliably automate steps 1–4 of the kill chain
Technical impact
Total control over the software or total information disclosure

CISA SSVC assessment, 2026-06-16.

Patch
Available – fixed in f8db6475a83649689c087a8f52486fcc53e627e9, da5c6b8ae47e414be47e5e04def15b25d5c962dc, cdedcd5aa3f3cb8b7ae0f87ab3a936d0bd583d66 +4
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

  1. Disclosed: evidence found.

    CVE published 14 Feb 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

  3. Weaponised: no evidence on record.

    No public exploit code indexed in Metasploit or Exploit-DB

  4. Exploited in the wild: no evidence on record.

    Not in CISA KEV and no source reports exploitation

  5. Observed by OffSeq Mirage: no evidence on record.

    No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

ProductAffectedFixed in
LinuxLinuxAffected
  • ≥ aa5fd0fb77486b8a6764ead8627baa14790e4280, < f8db6475a83649689c087a8f52486fcc53e627e9
Fixed in
  • f8db6475a83649689c087a8f52486fcc53e627e9
LinuxLinuxAffected
  • ≥ aa5fd0fb77486b8a6764ead8627baa14790e4280, < da5c6b8ae47e414be47e5e04def15b25d5c962dc
Fixed in
  • da5c6b8ae47e414be47e5e04def15b25d5c962dc
LinuxLinuxAffected
  • ≥ aa5fd0fb77486b8a6764ead8627baa14790e4280, < cdedcd5aa3f3cb8b7ae0f87ab3a936d0bd583d66
Fixed in
  • cdedcd5aa3f3cb8b7ae0f87ab3a936d0bd583d66
LinuxLinuxAffected
  • ≥ aa5fd0fb77486b8a6764ead8627baa14790e4280, < c43d0e787cbba569ec9d11579ed370b50fab6c9c
Fixed in
  • c43d0e787cbba569ec9d11579ed370b50fab6c9c
LinuxLinuxAffected
  • ≥ aa5fd0fb77486b8a6764ead8627baa14790e4280, < 986967a162142710076782d5b93daab93a892980
Fixed in
  • 986967a162142710076782d5b93daab93a892980
LinuxLinuxAffected
  • ≥ aa5fd0fb77486b8a6764ead8627baa14790e4280, < 11ba9f0dc865136174cb98834280fb21bbc950c7
Fixed in
  • 11ba9f0dc865136174cb98834280fb21bbc950c7

AI-suggested

A fix is available in the Linux kernel as indicated by the fixed commit versions. Users and administrators should update to a kernel version that includes the fix identified by the provided commit hashes. No other mitigations are specified.

Description

CVE-2026-23209 is a use-after-free vulnerability in the Linux kernel's macvlan network driver. It occurs during error recovery in the macvlan_common_newlink() function when creating a macvlan link with MACVLAN_MODE_SOURCE mode and certain MAC address parameters. The flaw can cause kernel crashes and potentially allow attackers with local privileges to cause denial of service or escalate privileges.

References

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