CVE-2026-23456
netfilter: nf_conntrack_h323: fix OOB read in decode_int() CONS case
Description
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().
INFO
Published Date :
April 3, 2026, 4:16 p.m.
Last Modified :
May 26, 2026, 2:41 p.m.
Remotely Exploit :
Yes !
Source :
416baaa9-dc9f-4396-8d5f-8c081fb06d67
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | 416baaa9-dc9f-4396-8d5f-8c081fb06d67 |
Solution
- Apply the patch for netfilter: nf_conntrack_h323.
- Add a boundary check for get_uint() arguments.
- Ensure buffer boundaries are validated before reading data.
Public PoC/Exploit Available at Github
CVE-2026-23456 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-23456.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-23456 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-23456
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
DSA and DLA for Debian last 14 days
Python
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-23456 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-23456 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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Initial Analysis by [email protected]
May. 26, 2026
Action Type Old Value New Value Added CWE CWE-125 Added CPE Configuration OR *cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:* *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.2 up to (excluding) 6.6.130 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.11 up to (excluding) 5.15.203 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 5.16 up to (excluding) 6.1.167 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.7 up to (excluding) 6.12.78 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.13 up to (excluding) 6.18.20 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 6.19 up to (excluding) 6.19.10 *cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* versions from (including) 2.6.17 up to (excluding) 5.10.253 Added Reference Type kernel.org: https://git.kernel.org/stable/c/1e3a3593162c96e8a8de48b1e14f60c3b57fca8a Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/41b417ff73a24b2c68134992cc44c88db27f482d Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/52235bf88159a1ef16434ab49e47e99c8a09ab20 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/6bce72daeccca9aa1746e92d6c3d4784e71f2ebb Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/774a434f8c9c8602a976b2536f65d0172a07f4d2 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/a2cd54b9348e485d338b3c132338a4410c99afaf Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/c95dc674ebf01ecfb40388b6facfc89b81fed3b7 Types: Patch Added Reference Type kernel.org: https://git.kernel.org/stable/c/fb6c3596823ec5dd09c2123340330d7448f51a59 Types: Patch -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Apr. 27, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H -
CVE Modified by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Apr. 18, 2026
Action Type Old Value New Value Added Reference https://git.kernel.org/stable/c/a2cd54b9348e485d338b3c132338a4410c99afaf Added Reference https://git.kernel.org/stable/c/c95dc674ebf01ecfb40388b6facfc89b81fed3b7 -
New CVE Received by 416baaa9-dc9f-4396-8d5f-8c081fb06d67
Apr. 03, 2026
Action Type Old Value New Value Added Description 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(). Added Reference https://git.kernel.org/stable/c/1e3a3593162c96e8a8de48b1e14f60c3b57fca8a Added Reference https://git.kernel.org/stable/c/41b417ff73a24b2c68134992cc44c88db27f482d Added Reference https://git.kernel.org/stable/c/52235bf88159a1ef16434ab49e47e99c8a09ab20 Added Reference https://git.kernel.org/stable/c/6bce72daeccca9aa1746e92d6c3d4784e71f2ebb Added Reference https://git.kernel.org/stable/c/774a434f8c9c8602a976b2536f65d0172a07f4d2 Added Reference https://git.kernel.org/stable/c/fb6c3596823ec5dd09c2123340330d7448f51a59