---
id: CVE-2026-44950
title: >-
  fs_read_glyphs() heap buffer overflow via cumulative glyph data overflow in
  libXfont2
summary: >-
  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…
severity: critical
cvss: 9
cvssVector: 'CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:H/I:H/A:H'
cvssSource: cna
vendor: SUSE
product: libXfont2-2
affected:
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.3-150000.3.6.1
  - libXfont2-2 >= ? < 2.0.7-160000.5.1
  - libXfont2-2 >= ? < 2.0.7-160000.5.1
  - libXfont2-2 >= ? < 2.0.7-160000.5.1
  - libXfont2-2 >= ? < 2.0.7-160000.5.1
  - libXfont2-2 >= ? < 2.0.7-160000.5.1
  - libXfont2-2 >= ? < 2.0.7-160000.5.1
  - libXfont2-2 >= ? < 2.0.7-160000.5.1
  - libXfont2-2 >= ? < 2.0.7-160000.5.1
  - libXfont2-2 >= ? < 2.0.3-3.6.1
  - libXfont2-2 >= ? < 2.0.3-3.6.1
  - libXfont2-2 >= ? < 2.0.3-3.6.1
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-09-10T17:19:50.287306Z'
published: '2026-09-10'
updated: '2026-09-10'
sourceUpdated: '2026-09-10T18:26:50.408Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-44950'
references:
  - url: 'https://bugzilla.suse.com/show_bug.cgi?id=CVE-2026-44950'
tags:
  - cve.org
epss: 0.00438
epssPercentile: 0.37524
ingestedAt: '2026-09-11T17:50:33.679Z'
---

## Overview

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.

## Affected

- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.3-150000.3.6.1`
- `libXfont2-2 >= ? < 2.0.7-160000.5.1`
- `libXfont2-2 >= ? < 2.0.7-160000.5.1`
- `libXfont2-2 >= ? < 2.0.7-160000.5.1`
- `libXfont2-2 >= ? < 2.0.7-160000.5.1`
- `libXfont2-2 >= ? < 2.0.7-160000.5.1`
- `libXfont2-2 >= ? < 2.0.7-160000.5.1`
- `libXfont2-2 >= ? < 2.0.7-160000.5.1`
- `libXfont2-2 >= ? < 2.0.7-160000.5.1`
- `libXfont2-2 >= ? < 2.0.3-3.6.1`
- `libXfont2-2 >= ? < 2.0.3-3.6.1`
- `libXfont2-2 >= ? < 2.0.3-3.6.1`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.