Bug 2496642 (CVE-2026-56003)

Summary:	CVE-2026-56003 libXfont2: computeProps Property Buffer Heap Buffer Overflow
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	gtanzill, jbuscemi, rhel-process-autobot, security-response-team, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:		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:
Deadline:	2026-07-08

Description OSIDB Bzimport 2026-07-02 18:37:43 UTC

In libXfont2's ComputeScaledProperties() function, a fixed-size property buffer of 70 slots (1120 bytes) is allocated. The
source font properties then trigger a write of 1 slot per unscaled match or 2 slots per scaledX/scaledY match, with no bounds check against the buffer capacity. The PCF parser does not deduplicate properties, so a malicious font can include arbitrarily many properties with the same name atom (e.g. 40 duplicate MIN_SPACE entries), exceeding the property buffer.

Comment 2 Tomas Hoger 2026-07-28 07:35:21 UTC

Upstream advisory:
https://www.openwall.com/lists/oss-security/2026/07/08/1

Upstream commit:
https://gitlab.freedesktop.org/xorg/lib/libxfont/-/commit/dff957a5158da038a282a59a31fe736702732939

Comment 3 errata-xmlrpc 2026-07-28 21:14:54 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2026:47103 https://access.redhat.com/errata/RHSA-2026:47103

Comment 21 errata-xmlrpc 2026-08-06 11:54:07 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10.0 Extended Update Support

Via RHSA-2026:51061 https://access.redhat.com/errata/RHSA-2026:51061

Comment 22 errata-xmlrpc 2026-08-06 12:04:54 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-2026:51060 https://access.redhat.com/errata/RHSA-2026:51060

Comment 23 errata-xmlrpc 2026-08-06 12:08:40 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions

Via RHSA-2026:51062 https://access.redhat.com/errata/RHSA-2026:51062

Comment 24 errata-xmlrpc 2026-08-06 12:27:10 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions

Via RHSA-2026:51058 https://access.redhat.com/errata/RHSA-2026:51058

Comment 25 errata-xmlrpc 2026-08-06 12:33:41 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-2026:51067 https://access.redhat.com/errata/RHSA-2026:51067

Comment 26 errata-xmlrpc 2026-08-06 12:34:10 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7 Extended Lifecycle Support

Via RHSA-2026:51063 https://access.redhat.com/errata/RHSA-2026:51063

Comment 27 errata-xmlrpc 2026-08-06 12:43:16 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.6 Extended Update Support

Via RHSA-2026:51059 https://access.redhat.com/errata/RHSA-2026:51059

Comment 28 errata-xmlrpc 2026-08-06 12:46:34 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-2026:51066 https://access.redhat.com/errata/RHSA-2026:51066