Bug 2454810 (CVE-2026-23455)

Summary:	CVE-2026-23455 kernel: netfilter: nf_conntrack_h323: check for zero length in DecodeQ931()
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	medium	Docs Contact:
Priority:	medium
Version:	unspecified	CC:	rhel-process-autobot, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in the Linux kernel's netfilter subsystem, specifically within the `nf_conntrack_h323` module. This vulnerability occurs in the `DecodeQ931()` function when processing a zero-length value from a packet. An integer underflow during a length calculation results in a large, incorrect value being passed to a subsequent function, leading to an out-of-bounds read. This could allow an attacker to cause a denial of service or potentially disclose sensitive information.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-04-03 16:01:58 UTC

In the Linux kernel, the following vulnerability has been resolved:

netfilter: nf_conntrack_h323: check for zero length in DecodeQ931()

In DecodeQ931(), the UserUserIE code path reads a 16-bit length from
the packet, then decrements it by 1 to skip the protocol discriminator
byte before passing it to DecodeH323_UserInformation(). If the encoded
length is 0, the decrement wraps to -1, which is then passed as a
large value to the decoder, leading to an out-of-bounds read.

Add a check to ensure len is positive after the decrement.

Comment 1 Jon Moroney 2026-04-03 19:20:01 UTC

Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026040317-CVE-2026-23455-f045@gregkh/T

Comment 3 errata-xmlrpc 2026-05-28 01:19:53 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:21557 https://access.redhat.com/errata/RHSA-2026:21557

Comment 4 errata-xmlrpc 2026-05-28 01:23:59 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:21556 https://access.redhat.com/errata/RHSA-2026:21556

Comment 5 errata-xmlrpc 2026-05-28 08:25:54 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2026:21706 https://access.redhat.com/errata/RHSA-2026:21706

Comment 6 errata-xmlrpc 2026-05-28 13:26:23 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2026:21745 https://access.redhat.com/errata/RHSA-2026:21745

Comment 7 errata-xmlrpc 2026-06-11 10:53:53 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.6 Extended Update Support

Via RHSA-2026:25218 https://access.redhat.com/errata/RHSA-2026:25218

Comment 8 errata-xmlrpc 2026-06-17 01:13:56 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions

Via RHSA-2026:26462 https://access.redhat.com/errata/RHSA-2026:26462

Comment 9 errata-xmlrpc 2026-06-17 06:33:35 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions

Via RHSA-2026:26515 https://access.redhat.com/errata/RHSA-2026:26515

Comment 10 errata-xmlrpc 2026-06-22 05:01:32 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions

Via RHSA-2026:27713 https://access.redhat.com/errata/RHSA-2026:27713

Comment 11 errata-xmlrpc 2026-07-01 00:15:52 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
  Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On

Via RHSA-2026:33899 https://access.redhat.com/errata/RHSA-2026:33899

Comment 12 errata-xmlrpc 2026-07-06 04:20:43 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7 Extended Lifecycle Support

Via RHSA-2026:35844 https://access.redhat.com/errata/RHSA-2026:35844

Comment 13 errata-xmlrpc 2026-07-06 04:51:26 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
  Red Hat Enterprise Linux 8.8 Telecommunications Update Service

Via RHSA-2026:35863 https://access.redhat.com/errata/RHSA-2026:35863

Comment 14 errata-xmlrpc 2026-07-06 14:26:41 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
  Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On

Via RHSA-2026:35896 https://access.redhat.com/errata/RHSA-2026:35896

Comment 15 errata-xmlrpc 2026-07-17 12:52:23 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7 Extended Lifecycle Support

Via RHSA-2026:41236 https://access.redhat.com/errata/RHSA-2026:41236