CVE-2025-15279
📋 TL;DR
A heap-based buffer overflow vulnerability in FontForge's BMP file parsing allows remote attackers to execute arbitrary code when users open malicious BMP files or visit malicious web pages. This affects users who process BMP files with vulnerable FontForge installations. Successful exploitation gives attackers the same privileges as the current user.
💻 Affected Systems
- FontForge
📦 What is this software?
Fontforge by Fontforge
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with attacker gaining the same privileges as the user running FontForge, potentially leading to data theft, ransomware deployment, or lateral movement.
Likely Case
Local privilege escalation or arbitrary code execution in the context of the current user, potentially compromising user data and system integrity.
If Mitigated
Denial of service or application crash if exploit fails, with no code execution due to security controls.
🎯 Exploit Status
Exploitation requires user interaction (opening malicious file) but the vulnerability itself is unauthenticated. The ZDI advisory suggests reliable exploitation is possible.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check vendor advisory for specific fixed version
Vendor Advisory: https://github.com/fontforge/fontforge/security/advisories (check for specific advisory)
Restart Required: Yes
Instructions:
1. Check current FontForge version
2. Visit FontForge GitHub releases page
3. Download and install the latest patched version
4. Restart FontForge and any dependent services
🔧 Temporary Workarounds
Disable BMP file processing
allConfigure FontForge to reject or not process BMP files
Configuration depends on FontForge setup - consider file type restrictions or input validation
User education and file restrictions
allTrain users to avoid opening untrusted BMP files and implement file type restrictions
🧯 If You Can't Patch
- Implement application whitelisting to prevent unauthorized FontForge execution
- Use sandboxing or virtualization for font processing workflows
🔍 How to Verify
Check if Vulnerable:
Check FontForge version against patched version in vendor advisoryCheck Version:
fontforge --version (Linux/macOS) or check About dialog (Windows)Verify Fix Applied:
Verify installed version matches or exceeds patched version from advisory📡 Detection & Monitoring
Log Indicators:
- FontForge crash logs with memory access violations
- Unexpected process creation from FontForge
Network Indicators:
- Downloads of suspicious BMP files followed by FontForge execution
SIEM Query:
Process creation where parent process is fontforge AND command line contains suspicious arguments OR file access events where fontforge opens .bmp files from untrusted sources