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VulnerabilityPublished Updated

CVE-2026-23278: Linux kernel · netfilter: nf_tables: always walk all pending catchall elements

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 7.8 High · fixed in eb0948fa13298212c5f8b30ee48efdae4389ab09 : patch Linux kernel soon.

Data as of 26 Oct 2026, 13:47 UTC

CVSS 3.1 base score
7.8High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.2% chance of exploitation in 30 days – higher than 12% 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 eb0948fa13298212c5f8b30ee48efdae4389ab09, de47a88c6b807910f05703fb6605f7efdaa11417, c4d4e86fda707d89eaba80e343321737375f8582 +9
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 20 Mar 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
  • >=6.1.36 <6.1.177
  • >=4.19.316 <4.20
  • >=5.4.262 <5.5
  • >=5.10.188 <5.11
  • >=5.15.121 <5.16
  • >=6.3.10 <6.4
Fixed in
  • eb0948fa13298212c5f8b30ee48efdae4389ab09
  • de47a88c6b807910f05703fb6605f7efdaa11417
  • c4d4e86fda707d89eaba80e343321737375f8582
  • 4830fb44d12f586f3f544609e086933649a9175a
  • 77c26b5056d693ffe5e9f040e946251cdb55ae55
  • 7cb9a23d7ae40a702577d3d8bacb7026f04ac2a9
  • 6.4
  • 6.1.177
  • 5.16
  • 5.11
  • 5.5
  • 4.20
LinuxLinuxAffected
  • =6.4
Fixed in–

AI-suggested

This vulnerability has been fixed in Linux kernel versions 5.11, 5.16, 6.1.177, and 6.4 and later. Users and administrators should upgrade to these or later kernel versions to remediate the issue. No additional mitigation is required once the system is updated.

Description

CVE-2026-23278 is a high-severity vulnerability in the Linux kernel's netfilter nf_tables subsystem. It involves improper handling of multiple pending catchall elements during transaction processing, which can lead to a use-after-free condition. This flaw was fixed in multiple Linux kernel versions starting from 5.11, 5.16, 6.1.177, and 6.4. The vulnerability has a CVSS score of 7.8, indicating significant impact on confidentiality, integrity, and availability.

References

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