CVE-2026-23456

High

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conntrack_h323: fix OOB read in decode_int() CONS case In decode_int(), the CONS case calls get_bits(bs, 2) to read a length value, then calls get_uint(bs, len) without checking that len bytes remain in the buffer. The existing boundary check only validates the 2 bits for get_bits(), not the subsequent 1-4 bytes that get_uint() reads. This allows a malformed H.323/RAS packet to cause a 1-4 byte slab-out-of-bounds read. Add a boundary check for len bytes after get_bits() and before get_uint().

Package Linux Kernel
Published 2026-04-03
Last modified 2026-05-26
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

8.2

out of 10
High
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
High
Vector string
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H

Weakness type

CWE-125

CVE-2026-23456 is a Out-of-bounds Read vulnerability

What is Out-of-bounds Read?

The product reads data past the end or before the beginning of the intended buffer. Learn more on MITRE CWE

Affected versions

Linux kernel versions 2.6.17 and later are affected. Fixed in 5.10.253, 5.15.203, 6.1.167, 6.6.130, 6.12.78, 6.18.20, 6.19.10, 7.0 and their respective stable series.

Affected from
≥ 2.6.17
Fixed in
✓ 5.10.253 5.10.x ✓ 5.15.203 5.15.x ✓ 6.1.167 6.1.x ✓ 6.6.130 6.6.x ✓ 6.12.78 6.12.x ✓ 6.18.20 6.18.x ✓ 6.19.10 6.19.x ✓ 7.0

References

The following references provide additional information about CVE-2026-23456 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

8 patch commits total View all on NVD

Frequently asked questions

  • What is CVE-2026-23456?

    CVE-2026-23456 is a High severity Linux kernel vulnerability with a CVSS score of 8.2 out of 10 , classified as an Out-of-bounds Read flaw (CWE-125) . It affects Linux kernel versions from 2.6.17 onward and has been patched in 5.10.253, 5.15.203, 6.1.167 and others. CVE-2026-23456 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2026-23456?

    CVE-2026-23456 has a CVSS score of 8.2 out of 10, rated High severity (CVSS 3.1). The vector string is CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H .

  • Is there a patch available for CVE-2026-23456?

    Yes — CVE-2026-23456 has been patched. Fixed versions include 5.10.253, 5.15.203, 6.1.167 and others. If you are running Linux kernel 2.6.17 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2026-23456 actively exploited?

    No — CVE-2026-23456 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

  • What is Out-of-bounds Read (CWE-125)?

    The product reads data past the end or before the beginning of the intended buffer. View CWE-125 on MITRE CWE →

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