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VulnerabilityPublished Updated

CVE-2026-23458: Linux kernel · netfilter: ctnetlink: fix use-after-free in ctnetlink_dump_exp_ct()

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High · fixed in f025171feef2ac65663d7986f1d5ff0c28d6b2a9 : 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 2% 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, 2026-10-16.

Patch
Available – fixed in f025171feef2ac65663d7986f1d5ff0c28d6b2a9, f04cc86d59906513d2d62183b882966fc0ae0390, d8cd0efbccc5cfb0a80da744a7da76e1333ab925 +5
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 3 Apr 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
  • ≥ e844a928431fa8f1359d1f4f2cef53d9b446bf52, < f025171feef2ac65663d7986f1d5ff0c28d6b2a9
Fixed in
  • f025171feef2ac65663d7986f1d5ff0c28d6b2a9
LinuxLinuxAffected
  • ≥ e844a928431fa8f1359d1f4f2cef53d9b446bf52, < f04cc86d59906513d2d62183b882966fc0ae0390
Fixed in
  • f04cc86d59906513d2d62183b882966fc0ae0390
LinuxLinuxAffected
  • ≥ e844a928431fa8f1359d1f4f2cef53d9b446bf52, < d8cd0efbccc5cfb0a80da744a7da76e1333ab925
Fixed in
  • d8cd0efbccc5cfb0a80da744a7da76e1333ab925
LinuxLinuxAffected
  • ≥ e844a928431fa8f1359d1f4f2cef53d9b446bf52, < cd541f15b60e2257441398cf495d978f816d09f8
Fixed in
  • cd541f15b60e2257441398cf495d978f816d09f8
LinuxLinuxAffected
  • ≥ e844a928431fa8f1359d1f4f2cef53d9b446bf52, < bdf2724eefd4455a66863abb025bab8d3aa98c57
Fixed in
  • bdf2724eefd4455a66863abb025bab8d3aa98c57
LinuxLinuxAffected
  • ≥ e844a928431fa8f1359d1f4f2cef53d9b446bf52, < 9821b47f669eb82791fa0b1a6ebaf9aa219bea72
Fixed in
  • 9821b47f669eb82791fa0b1a6ebaf9aa219bea72

AI-suggested

A fix is available and has been applied in specific Linux kernel commits identified by the fixedVersions hashes. Users should update their Linux kernel to a version that includes these fixes. No additional mitigation steps are indicated by the vendor advisory.

Description

CVE-2026-23458 is a use-after-free vulnerability in the Linux kernel's netfilter ctnetlink subsystem. The flaw occurs in the ctnetlink_dump_exp_ct() function, where a conntrack pointer is stored but its reference is dropped prematurely during multi-round netlink dumps. This leads to dereferencing freed memory, causing a use-after-free condition. The issue is fixed by adding proper start and done callbacks to manage the conntrack reference across dump rounds.

References

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