CVE-2026-56002 PUBLISHED

libXfont2 PCF Font Parsing Heap Buffer Overflow

Assigner: suse
Reserved: 18.06.2026 Published: 08.07.2026 Updated: 08.07.2026

A heap bufferflow in pcfReadFont() due to missing glyph bounds checking in libXfont2 before 2.0.8 allows attackers authenticated as X client to execute code within the X server.

Metrics

CVSS 3.1

CVSS Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H
CVSS Score: 8.5

Attack Vector	Network	Scope	Changed
Attack Complexity	High	Confidentiality Impact	High
Privileges Required	Low	Integrity Impact	High
User Interaction	None	Availability Impact	High

CVSS 3.1

Product Status

Vendor	X.Org
Product	libXfont2
Versions	Default: unaffected affected from 0 to 2.0.8 (excl.)

Credits

Anonymous working with Trend Micro Zero Day Initiative. finder

References

https://gitlab.freedesktop.org/xorg/lib/libxfont/-/commit/b4389e0b1d84a690b819bb27b1439968811a3674
https://www.openwall.com/lists/oss-security/2026/07/08/1

Problem Types

CWE-122 Heap-based buffer overflow CWE

Impacts

CAPEC-234 Hijacking a privileged process