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VulnerabilityPublished Updated

CVE-2026-23456: Linux kernel · Out-of-bounds Read

Affects Linux kernelSource CVE Database V5

0

Not known to be exploited · CVSS 8.2 High · fixed in fb6c3596823ec5dd09c2123340330d7448f51a59 : patch Linux kernel soon.

Data as of 26 Oct 2026, 17:30 UTC

CVSS 3.1 base score
8.2High
How severe the flaw is on the 0–10 CVSS scale.
EPSS
0.5% chance of exploitation in 30 days – higher than 44% 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 can reliably automate steps 1–4 of the kill chain
Technical impact
Limited control over the software or limited information exposure

CISA SSVC assessment, 2026-10-16.

Patch
Available – fixed in fb6c3596823ec5dd09c2123340330d7448f51a59, c95dc674ebf01ecfb40388b6facfc89b81fed3b7, a2cd54b9348e485d338b3c132338a4410c99afaf +5
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/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
  • ≥ 5e35941d990123f155b02d5663e51a24f816b6f3, < fb6c3596823ec5dd09c2123340330d7448f51a59
Fixed in
  • fb6c3596823ec5dd09c2123340330d7448f51a59
LinuxLinuxAffected
  • ≥ 5e35941d990123f155b02d5663e51a24f816b6f3, < c95dc674ebf01ecfb40388b6facfc89b81fed3b7
Fixed in
  • c95dc674ebf01ecfb40388b6facfc89b81fed3b7
LinuxLinuxAffected
  • ≥ 5e35941d990123f155b02d5663e51a24f816b6f3, < a2cd54b9348e485d338b3c132338a4410c99afaf
Fixed in
  • a2cd54b9348e485d338b3c132338a4410c99afaf
LinuxLinuxAffected
  • ≥ 5e35941d990123f155b02d5663e51a24f816b6f3, < 52235bf88159a1ef16434ab49e47e99c8a09ab20
Fixed in
  • 52235bf88159a1ef16434ab49e47e99c8a09ab20
LinuxLinuxAffected
  • ≥ 5e35941d990123f155b02d5663e51a24f816b6f3, < 774a434f8c9c8602a976b2536f65d0172a07f4d2
Fixed in
  • 774a434f8c9c8602a976b2536f65d0172a07f4d2
LinuxLinuxAffected
  • ≥ 5e35941d990123f155b02d5663e51a24f816b6f3, < 41b417ff73a24b2c68134992cc44c88db27f482d
Fixed in
  • 41b417ff73a24b2c68134992cc44c88db27f482d

AI-suggested

This vulnerability has been fixed in multiple Linux kernel commits as listed in the established facts. Users and administrators should update their Linux kernel to a version that includes these fixes. There is no indication that additional mitigations are required beyond applying the official patches.

Description

A high-severity vulnerability (CVE-2026-23456) in the Linux kernel's netfilter nf_conntrack_h323 module allows an out-of-bounds read of 1-4 bytes due to improper boundary checking in the decode_int() function. This flaw occurs when processing malformed H.323/RAS packets, potentially causing a slab-out-of-bounds read. The issue has been fixed in specific Linux kernel commits.

References

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