CVE-2026-44950 Affecting libxfont package, versions <1:2.0.6-1+deb13u1


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.26% (17th percentile)

Do your applications use this vulnerable package?

In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.

Test your applications
  • Snyk IDSNYK-ECHOLATEST-LIBXFONT-18533225
  • published5 Aug 2026
  • disclosed10 Sept 2026

Introduced: 5 Aug 2026

CVE-2026-44950  (opens in a new tab)

How to fix?

Upgrade Echo:latest libxfont to version 1:2.0.6-1+deb13u1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream libxfont package and not the libxfont package as distributed by Echo. See How to fix? for Echo:latest 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