Ubuntu libXfont Important Denial Of Service Heap Overflow Vuln 8560

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... Read the Full Advisory

Several security issues were fixed in libXfont.

Software Description:

- libxfont: X11 font rasterisation library

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.

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...

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.

CVE-2017-16611, CVE-2026-56001, CVE-2026-56002, CVE-2026-56003

Ubuntu Security Notice USN-8560-1

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