Meta has issued a security advisory regarding a newly discovered vulnerability in the FreeType open-source font rendering library. Tracked as CVE-2025-27363, this flaw has been assigned a CVSS score of 8.1, categorizing it as a high-severity issue. Security experts warn that this vulnerability may have been actively exploited in real-world attacks.
What is CVE-2025-27363?
This flaw is an out-of-bounds write vulnerability found in FreeType versions 2.13.0 and below. It originates from a miscalculation in memory allocation when parsing TrueType GX and variable font files. Specifically, the flaw occurs when:
- A signed short value is assigned to an unsigned long, causing an integer overflow.
- A small heap buffer is allocated due to incorrect calculations.
- Up to six signed long integers are written out of bounds, leading to potential remote code execution.
This means an attacker could craft a malicious font file that, when processed, allows them to execute arbitrary code and potentially take control of the affected system.
FreeType Developer Confirms Fix
Security researcher Werner Lemberg, a developer of FreeType, confirmed that a fix for this issue was introduced almost two years ago. According to Lemberg, any version above 2.13.0 is no longer affected by this vulnerability.
Affected Linux Distributions
Despite the fix being available, several popular Linux distributions are still using outdated versions of FreeType, making them vulnerable to this exploit. According to a report on the Open Source Security mailing list (oss-security), the following distributions remain affected:
- AlmaLinux
- Alpine Linux
- Amazon Linux 2
- Debian Stable / Devuan
- RHEL / CentOS Stream / AlmaLinux 8 & 9
- GNU Guix
- Mageia
- OpenMandriva
- openSUSE Leap
- Slackware
- Ubuntu 22.04
If you are using any of these distributions, it is highly recommended that you update FreeType immediately to patch this security flaw.
How to Protect Yourself
To mitigate the risk of exploitation, users and system administrators should take the following steps:
- Check Your FreeType Version: Run the command:
freetype-config --versionor check package details usingdpkg -l | grep freetype(Debian-based) orrpm -qa | grep freetype(RHEL-based). - Update FreeType Immediately: Upgrade to version 2.13.3 or later.
- Apply Security Patches: Keep your Linux distribution updated with the latest security fixes.
- Enable System Security Measures: Use AppArmor, SELinux, or other security frameworks to limit execution risks.
- Monitor Security Advisories: Stay updated on security reports from Debian Security Tracker and Red Hat Security.
Conclusion
With the increasing number of zero-day exploits targeting system vulnerabilities, it is critical to patch security flaws. CVE-2025-27363 is a serious risk that, if exploited, can lead to remote code execution and full system compromise.
If your system runs an affected version of FreeType, update immediately to version 2.13.3 or later to protect your data and infrastructure.
Milena Dimitrova
An inspired writer and content manager who has been with SensorsTechForum since the project started. A professional with 10+ years of experience in creating engaging content. Focused on user privacy and malware development, she strongly believes in a world where cybersecurity plays a central role. If common sense makes no sense, she will be there to take notes. Those notes may later turn into articles! Follow Milena @Milenyim
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