Linux Kernel up to 7.0-rc4 nf_conntrack_h323 decode_int out-of-bounds

CVSS Meta Temp Score
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CTI Interest Score
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5.8$0-$5k0.00

Summaryinfo

A vulnerability has been found in Linux Kernel up to 7.0-rc4 and classified as critical. This impacts the function decode_int of the component nf_conntrack_h323. Performing a manipulation results in out-of-bounds. This vulnerability is known as CVE-2026-23456. No exploit is available. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in Linux Kernel up to 7.0-rc4. It has been classified as problematic. This affects the function decode_int of the component nf_conntrack_h323. The manipulation with an unknown input leads to a out-of-bounds vulnerability. CWE is classifying the issue as CWE-125. The product reads data past the end, or before the beginning, of the intended buffer. This is going to have an impact on confidentiality. The summary by CVE is:

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().

It is possible to read the advisory at git.kernel.org. This vulnerability is uniquely identified as CVE-2026-23456 since 01/13/2026. Technical details of the vulnerability are known, but there is no available exploit.

The vulnerability scanner Nessus provides a plugin with the ID 311783 (Debian dla-4561 : linux-config-6.1 - security update), which helps to determine the existence of the flaw in a target environment.

Upgrading to version 6.1.167, 6.6.130, 6.12.78, 6.18.20, 6.19.10 or 7.0-rc5 eliminates this vulnerability. Applying the patch 41b417ff73a24b2c68134992cc44c88db27f482d/52235bf88159a1ef16434ab49e47e99c8a09ab20/774a434f8c9c8602a976b2536f65d0172a07f4d2/6bce72daeccca9aa1746e92d6c3d4784e71f2ebb/fb6c3596823ec5dd09c2123340330d7448f51a59/1e3a3593162c96e8a8de48b1e14f60c3b57fca8a is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the databases at Tenable (311783), EUVD (EUVD-2026-18712) and CERT Bund (WID-SEC-2026-0985). Statistical analysis made it clear that VulDB provides the best quality for vulnerability data.

Affected

  • Google Container-Optimized OS
  • Debian Linux
  • Amazon Linux 2
  • Red Hat Enterprise Linux
  • Ubuntu Linux
  • SUSE Linux
  • Oracle Linux
  • SUSE openSUSE
  • Open Source Linux Kernel
  • RESF Rocky Linux
  • Microsoft Azure Linux

Productinfo

Type

Vendor

Name

Version

License

Website

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 5.8
VulDB Meta Temp Score: 5.8

VulDB Base Score: 3.5
VulDB Temp Score: 3.4
VulDB Vector: 🔒
VulDB Reliability: 🔍

CNA Base Score: 8.2
CNA Vector (Linux): 🔒

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Out-of-bounds
CWE: CWE-125 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined

EPSS Score: 🔒
EPSS Percentile: 🔒

Price Prediction: 🔍
Current Price Estimation: 🔒

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Nessus ID: 311783
Nessus Name: Debian dla-4561 : linux-config-6.1 - security update

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.1.167/6.6.130/6.12.78/6.18.20/6.19.10/7.0-rc5
Patch: 41b417ff73a24b2c68134992cc44c88db27f482d/52235bf88159a1ef16434ab49e47e99c8a09ab20/774a434f8c9c8602a976b2536f65d0172a07f4d2/6bce72daeccca9aa1746e92d6c3d4784e71f2ebb/fb6c3596823ec5dd09c2123340330d7448f51a59/1e3a3593162c96e8a8de48b1e14f60c3b57fca8a

Timelineinfo

01/13/2026 CVE reserved
04/03/2026 +79 days Advisory disclosed
04/03/2026 +0 days VulDB entry created
06/25/2026 +83 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-23456 (🔒)
GCVE (CVE): GCVE-0-2026-23456
GCVE (VulDB): GCVE-100-355155
EUVD: 🔒
CERT Bund: WID-SEC-2026-0985 - Linux Kernel: Mehrere Schwachstellen

Entryinfo

Created: 04/03/2026 18:15
Updated: 06/25/2026 10:31
Changes: 04/03/2026 18:15 (59), 04/19/2026 21:50 (1), 05/04/2026 14:48 (2), 05/27/2026 03:52 (11), 06/25/2026 10:31 (7)
Complete: 🔍
Cache ID: 216::103

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