Bug 2496642 (CVE-2026-56003) - CVE-2026-56003 libXfont2: computeProps Property Buffer Heap Buffer Overflow
Summary: CVE-2026-56003 libXfont2: computeProps Property Buffer Heap Buffer Overflow
Keywords:
Status: NEW
Alias: CVE-2026-56003
Deadline: 2026-07-08
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security
QA Contact:
URL:
Whiteboard:
Depends On:
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-07-02 18:37 UTC by OSIDB Bzimport
Modified: 2026-08-06 12:46 UTC (History)
5 users (show)

Fixed In Version:
Clone Of:
Environment:
Last Closed:
Embargoed:

Attachments (Terms of Use)


Links
System ID Private Priority Status Summary Last Updated
Red Hat Product Errata RHSA-2026:47103 0 None None None 2026-07-28 21:14:55 UTC
Red Hat Product Errata RHSA-2026:51058 0 None None None 2026-08-06 12:27:11 UTC
Red Hat Product Errata RHSA-2026:51059 0 None None None 2026-08-06 12:43:17 UTC
Red Hat Product Errata RHSA-2026:51060 0 None None None 2026-08-06 12:04:55 UTC
Red Hat Product Errata RHSA-2026:51061 0 None None None 2026-08-06 11:54:08 UTC
Red Hat Product Errata RHSA-2026:51062 0 None None None 2026-08-06 12:08:40 UTC
Red Hat Product Errata RHSA-2026:51063 0 None None None 2026-08-06 12:34:11 UTC
Red Hat Product Errata RHSA-2026:51066 0 None None None 2026-08-06 12:46:35 UTC
Red Hat Product Errata RHSA-2026:51067 0 None None None 2026-08-06 12:33:42 UTC

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
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