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VulnerabilityPublished Updated

CVE-2026-23231: Linux kernel · netfilter: nf_tables: fix use-after-free in nf_tables_addchain()

Affects Linux kernelSource CVE Database V5

0

Public exploit available (Exploit-DB) · CVSS 7.8 High · fixed in f3fe58ce37926a10115ede527d59b91bcc05400a : patch Linux kernel as a priority.

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
1.0% chance of exploitation in 30 days – higher than 63% 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 f3fe58ce37926a10115ede527d59b91bcc05400a, dbd0af8083dd201f07c49110b2ee93710abdff28, 7017745068a9068904e1e7a1b170a5785647cc81 +3
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Exploitation evidence

t = 0 is the CVE’s publication on cve.org

  1. Disclosed: evidence found.

    CVE published 4 Mar 2026

  2. Detectable: no evidence on record.

    No public nuclei template indexed

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

    Not in CISA KEV and no source reports exploitation

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

    No attack traffic recorded by OffSeq Mirage sensors

Timeline

  1. CVE ID reserved

    by kernel.org

    , 50 days before disclosure

  2. CVE published

    on cve.org

    , t = 0

  3. First Exploit-DB entry (opens in a new tab)

    Linux nf_tables 6.19.3 - Local Privilege Escalation

    , 61 days after disclosure

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
  • ≥ 91c7b38dc9f0de4f7f444b796d14476bc12df7bc, < f3fe58ce37926a10115ede527d59b91bcc05400a
Fixed in
  • f3fe58ce37926a10115ede527d59b91bcc05400a
LinuxLinuxAffected
  • ≥ 91c7b38dc9f0de4f7f444b796d14476bc12df7bc, < dbd0af8083dd201f07c49110b2ee93710abdff28
Fixed in
  • dbd0af8083dd201f07c49110b2ee93710abdff28
LinuxLinuxAffected
  • ≥ 91c7b38dc9f0de4f7f444b796d14476bc12df7bc, < 7017745068a9068904e1e7a1b170a5785647cc81
Fixed in
  • 7017745068a9068904e1e7a1b170a5785647cc81
LinuxLinuxAffected
  • ≥ 91c7b38dc9f0de4f7f444b796d14476bc12df7bc, < 71e99ee20fc3f662555118cf1159443250647533
Fixed in
  • 71e99ee20fc3f662555118cf1159443250647533
LinuxLinuxAffected
  • ≥ 91c7b38dc9f0de4f7f444b796d14476bc12df7bc, < 2f9a4ffeb763aec822f8ff3d1e82202d27d46d4b
Fixed in
  • 2f9a4ffeb763aec822f8ff3d1e82202d27d46d4b
LinuxLinuxAffected
  • ≥ 91c7b38dc9f0de4f7f444b796d14476bc12df7bc, < 2a6586ecfa4ce1413daaafee250d2590e05f1a33
Fixed in
  • 2a6586ecfa4ce1413daaafee250d2590e05f1a33

AI-suggested

A fix is available in the Linux kernel as indicated by the fixed commit versions. Users and administrators should update to a patched kernel version containing these fixes. Since this is a kernel-level vulnerability, applying the official kernel updates is the recommended remediation. No additional mitigations are specified or required beyond applying the patch.

Description

CVE-2026-23231 is a use-after-free vulnerability in the Linux kernel's netfilter nf_tables subsystem, specifically in the nf_tables_addchain() function. The flaw occurs when an error during hook registration leads to premature freeing of a chain without waiting for all readers to finish, causing potential memory corruption. This affects control-plane operations and packet processing paths. The vulnerability has been fixed by adding an RCU synchronization call to ensure safe memory reclamation.

References

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