PT-2026-56383 · Libxfont2 · Libxfont2

Published 2026-07-08 · Updated 2026-07-08 · CVE-2026-56001

Positive Technologies (AI Summary)

CVSS v3.1

8.5

High

Base vector

AV:N/AC:H/PR:L/UI:N/S:C/C:H/I:H/A:H

Name of the Vulnerable Software and Affected Versions libXfont2 versions prior to 2.0.8

Description A heap-based buffer overflow exists in the BitmapScaleBitmaps() function. The issue is caused by an integer overflow where a 32-bit size calculation wraps, resulting in an undersized heap allocation and subsequent out-of-bounds writes. An attacker with access to the X Server can trigger this by providing crafted font bitmap data, potentially leading to arbitrary code execution within the X server process and takeover of the display server context.

Recommendations Upgrade libXfont2 to version 2.0.8.

Fix

Heap Based Buffer Overflow

Weakness Enumeration

CWE-122

Related Identifiers

CVE-2026-56001

Affected Products

Libxfont2

References · 6

• https://openwall.com/lists/oss-security/2026/07/08/1 · Vendor Advisory
• https://gitlab.freedesktop.org/xorg/lib/libxfont/-/commit/be0b08e2d354138d3222b4490e2a77c6ee42f778 · Patch
• https://nvd.nist.gov/vuln/detail/CVE-2026-56001 · Security Note
• https://twitter.com/UpwindMDR/status/2074804564641865837 · Twitter Post
• https://twitter.com/infoflowcloud/status/2074826218898116907 · Twitter Post
• https://twitter.com/CVEnew/status/2074825578025193668 · Twitter Post