USN-7917-1: fontTools vulnerabilities

USN-7917-1: fontTools vulnerabilities

Publication date: 9 December 2025
Overview: Several security issues were fixed in fontTools.

Packages
fonttools - a library for manipulating fonts, written in Python

Details
It was discovered that the subsetting module of fontTools was vulnerable to
an XML External Entity (XEE) attack. An unauthenticated remote attacker
could possibly use this issue to include arbitrary files from the file
system or make web requests from the host system. This issue only affected
Ubuntu 22.04 LTS. (CVE-2023-45139)

It was discovered that fontTools was vulnerable to path traversal attacks.
If a user or automated system were tricked into extracting a specially
crafted .designspace file, an attacker could possibly use this issue to
write arbitrary files outside the target directory, resulting in remote
code execution. This issue only affected Ubuntu 24.04 LTS, Ubuntu 25.04
and Ubuntu 25.10. (CVE-2025-66034)

Update instructions
In general, a standard system update will make all the necessary changes.
The problem can be corrected by updating your system to the following package versions:

25.10 questing

• fonttools – 4.55.3-2ubuntu0.25.10.1
• python3-fonttools – 4.55.3-2ubuntu0.25.10.1

25.04 plucky

• fonttools – 4.55.3-2ubuntu0.25.04.1
• python3-fonttools – 4.55.3-2ubuntu0.25.04.1

24.04 LTS noble

• fonttools – 4.46.0-1ubuntu0.1~esm1
• python3-fonttools – 4.46.0-1ubuntu0.1~esm1

22.04 LTS jammy

• fonttools – 4.29.1-2ubuntu0.1~esm1
• python3-fonttools – 4.29.1-2ubuntu0.1~esm1