CVE-2025-27363
📋 TL;DR
This CVE describes an out-of-bounds write vulnerability in FreeType versions 2.13.0 and below when parsing TrueType GX and variable font files. The vulnerability allows arbitrary code execution through heap corruption and may have been exploited in the wild. Any system or application using vulnerable FreeType versions for font rendering is affected.
💻 Affected Systems
- FreeType
📦 What is this software?
Freetype by Freetype
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with remote code execution leading to complete data loss, lateral movement, and persistent backdoors.
Likely Case
Application crash leading to denial of service, with potential for code execution in memory-safe environments.
If Mitigated
Application crash without code execution if exploit fails or memory protections are in place.
🎯 Exploit Status
Exploitation requires processing malicious font files. The advisory mentions possible in-the-wild exploitation.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: FreeType 2.13.1 or later
Vendor Advisory: https://www.facebook.com/security/advisories/cve-2025-27363
Restart Required: No
Instructions:
1. Update FreeType to version 2.13.1 or later. 2. For embedded systems, rebuild with patched FreeType library. 3. For Linux distributions, use package manager updates. 4. For applications bundling FreeType, update the bundled library.
🔧 Temporary Workarounds
Disable TrueType GX and variable font processing
allConfigure applications to avoid processing TrueType GX and variable fonts if not required.
🧯 If You Can't Patch
- Implement application allowlisting to prevent execution of untrusted font files.
- Use memory protection mechanisms like ASLR and DEP to reduce exploit success.
🔍 How to Verify
Check if Vulnerable:
Check FreeType version with 'freetype-config --version' or examine library files. Versions 2.13.0 and below are vulnerable.Check Version:
freetype-config --versionVerify Fix Applied:
Verify FreeType version is 2.13.1 or later using version check command.📡 Detection & Monitoring
Log Indicators:
- Application crashes related to font processing
- Memory access violation errors in application logs
Network Indicators:
- Unusual font file downloads
- Font file processing from untrusted sources
SIEM Query:
search for 'freetype' AND ('crash' OR 'segmentation fault' OR 'access violation') in application logs🔗 References
- https://www.facebook.com/security/advisories/cve-2025-27363
- http://www.openwall.com/lists/oss-security/2025/03/13/1
- http://www.openwall.com/lists/oss-security/2025/03/13/11
- http://www.openwall.com/lists/oss-security/2025/03/13/12
- http://www.openwall.com/lists/oss-security/2025/03/13/2
- http://www.openwall.com/lists/oss-security/2025/03/13/3
- http://www.openwall.com/lists/oss-security/2025/03/13/8
- http://www.openwall.com/lists/oss-security/2025/03/14/1
- http://www.openwall.com/lists/oss-security/2025/03/14/2
- http://www.openwall.com/lists/oss-security/2025/03/14/3
- http://www.openwall.com/lists/oss-security/2025/03/14/4
- http://www.openwall.com/lists/oss-security/2025/05/06/3
- https://lists.debian.org/debian-lts-announce/2025/03/msg00030.html
- https://source.android.com/docs/security/bulletin/2025-05-01
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2025-27363
