CVE-2026-56002
libXfont2: PCF Font Parsing Heap Buffer Overflow
Severity
ImportantRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · July 8, 2026
Updated · August 7, 2026
Description
A flaw was found in libXfont2. A specially crafted PCF (Portable Compiled Format) font file, when processed by libXfont2, can lead to a buffer overflow. This occurs because the font parsing process does not properly validate the size of a bitmap buffer against the glyph metrics provided in the malicious font file. An attacker could exploit this vulnerability by providing a malicious font, potentially leading to arbitrary code execution or a denial of service.
Statement
This is an Important flaw in libXfont2, affecting Red Hat Enterprise Linux. A heap buffer overflow during PCF font file parsing can lead to arbitrary code execution or denial of service. Exploitation requires processing a specially crafted font file, but does not necessitate rendering.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
No mitigation is specified in collected source.
CVSS / CWE
CVSS 3.1 · 7.3CVSS:3.1/AV:L/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:H
CWE-787 · Out-of-bounds Write