CVE-2026-44950 Affecting libXfont2 package, versions <0:2.0.3-12.el9_8.3


Severity

Recommended
high

Based on AlmaLinux security rating.

Threat Intelligence

EPSS
0.26% (17th percentile)

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  • Snyk IDSNYK-ALMALINUX9-LIBXFONT2-18959501
  • published19 Aug 2026
  • disclosed17 Aug 2026

Introduced: 17 Aug 2026

CVE-2026-44950  (opens in a new tab)

How to fix?

Upgrade AlmaLinux:9 libXfont2 to version 0:2.0.3-12.el9_8.3 or higher.
This issue was patched in ALSA-2026:55447.

NVD Description

Note: Versions mentioned in the description apply only to the upstream libXfont2 package and not the libXfont2 package as distributed by AlmaLinux. See How to fix? for AlmaLinux:9 relevant fixed versions and status.

fs_read_glyphs() in the libXfont2 font-server client (src/fc/fserve.c) copies each glyph's bitmap into a single buffer. Existing checks validates only that the source slice (position, length) lies within the source bitmap buffer. It does not check whether the running destination cursor has exceeded the allocation.

A malicious font server can send overlapping source offsets -- for example 1000 glyphs each referencing {position:0, length:64} with nbytes=64. Each individual source range passes the existing validation, but the cumulative writes total 64000 bytes into a 64-byte destination buffer. This is a heap buffer overflow with attacker-controlled content.

CVSS Base Scores

version 3.1