CVE-2026-56003 Details
Description
A heap buffer overflow due to missing size checking in the property buffer when parsing PCF files in libXfont2 ComputeScaledProperties() before libXfont2 before 2.0.8 could be used by attackers using authenticated X clients to execute code within the X server.
A heap buffer overflow vulnerability has been identified in libXfont2 versions prior to 2.0.8. The issue arises in the ComputeScaledProperties() function, where a fixed-size property buffer is allocated without proper size checks. This flaw can be exploited by authenticated X clients to execute code within the X server. The vulnerability allows for the inclusion of excessive duplicate properties in a malicious PCF font, leading to an overflow of the allocated buffer.
Users can upgrade to libXfont2 version 2.0.8 to address this vulnerability.
Metrics
CVSS 4.0 Severity and Vector Strings:
No CVSS 4.0 data is available for this CVE.
CVSS 3.x Severity and Vector Strings:
No data available for CVSS Version 2.0 on this CVE.
CISA-ADP
Assessed Jul 8, 2026References to Advisories, Solutions, and Tools
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| URL | Source(s) | Tag(s) |
|---|---|---|
| https://gitlab.freedesktop.org/xorg/lib/libxfont/-/commit/dff957a5158da038a282a59a31fe736702732939 | [email protected] | Patch |
| https://www.openwall.com/lists/oss-security/2026/07/08/1 | [email protected] | Mailing ListPatchThird Party Advisory |
Weakness Enumeration
| CWE-ID | CWE Name | Source |
|---|---|---|
| CWE-122 | Heap-based Buffer Overflow | [email protected] |
Affected Products
| Product | Versions |
|---|---|
| x libxfont | >= 2.0.0, < 2.0.8 |
CPE
Remediation
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Change History
5 change records found show changes
| Date | Action | Recorded By |
|---|---|---|
| Jul 9, 2026 | Reanalysis | [email protected] |
| Jul 9, 2026 | Initial Analysis | [email protected] |
| Jul 9, 2026 | CVE Modified | CISA-ADP |
| Jul 8, 2026 | CVE Modified | CISA-ADP |
| Jul 8, 2026 | New CVE Received | [email protected] |