========================================================================== Ubuntu Security Notice USN-8560-1 July 20, 2026
libxfont vulnerabilities
==========================================================================
A security issue affects these releases of Ubuntu and its derivatives:
- Ubuntu 26.04 LTS
- Ubuntu 24.04 LTS
- Ubuntu 22.04 LTS
- Ubuntu 20.04 LTS
- Ubuntu 18.04 LTS
- Ubuntu 16.04 LTS
- Ubuntu 14.04 LTS
Summary:
Several security issues were fixed in libXfont.
Software Description:
- libxfont: X11 font rasterisation library
Details:
It was discovered that libXfont incorrectly handled scaling bitmap
fonts, leading to a heap buffer overflow. An attacker able to access
the X server could use this issue to cause libXfont to crash,
resulting in a denial of service, or possibly execute arbitrary code.
(CVE-2026-56001)
It was discovered that libXfont did not properly check glyph bounds
when reading PCF fonts, leading to a heap buffer overflow. An
authenticated X client could use this issue to cause libXfont to
crash, resulting in a denial of service, or possibly execute arbitrary
code. (CVE-2026-56002)
It was discovered that libXfont did not properly check the size of the
property buffer when parsing PCF fonts, leading to a heap buffer
overflow. An authenticated X client could use this issue to cause
libXfont to crash, resulting in a denial of service, or possibly
execute arbitrary code. (CVE-2026-56003)
Update instructions:
The problem can be corrected by updating your system to the following
package versions:
Ubuntu 26.04 LTS
libxfont2 1:2.0.6-2ubuntu0.2
Ubuntu 24.04 LTS
libxfont2 1:2.0.6-1+deb13u1build0.24.04.2
Ubuntu 22.04 LTS
libxfont2 1:2.0.5-1ubuntu0.2
Ubuntu 20.04 LTS
libxfont2 1:2.0.3-1ubuntu0.20.04.1~esm2
Available with Ubuntu Pro
Ubuntu 18.04 LTS
libxfont2 1:2.0.3-1ubuntu0.1~esm2
Available with Ubuntu Pro
Ubuntu 16.04 LTS
libxfont1 1:1.5.1-1ubuntu0.16.04.4+esm2
Available with Ubuntu Pro
Ubuntu 14.04 LTS
libxfont1 1:1.4.7-1ubuntu0.4+esm2
Available with Ubuntu Pro
In general, a standard system update will make all the necessary changes.
References:
https://ubuntu.com/security/notices/USN-8560-1
CVE-2017-16611, CVE-2026-56001, CVE-2026-56002, CVE-2026-56003
Package Information:
https://launchpad.net/ubuntu/+source/libxfont/1:2.0.6-2ubuntu0.2
https://launchpad.net/ubuntu/+source/libxfont/1:2.0.6-1+deb13u1build0.24.04.2
https://launchpad.net/ubuntu/+source/libxfont/1:2.0.5-1ubuntu0.2
signature.asc
Description: OpenPGP digital signature
