CVE-2025-50949
📋 TL;DR
FontForge v20230101 contains a memory leak in the DlgCreate8 component that allows attackers to cause denial of service through resource exhaustion. This affects users who process untrusted font files with the vulnerable version. The vulnerability is triggered when specific dialog creation operations occur repeatedly.
💻 Affected Systems
- FontForge
📦 What is this software?
Fontforge by Fontforge
⚠️ Risk & Real-World Impact
Worst Case
Sustained exploitation could lead to complete system memory exhaustion, causing FontForge to crash and potentially affecting system stability if memory isn't properly reclaimed.
Likely Case
FontForge becomes unresponsive or crashes when processing malicious font files, disrupting font editing workflows.
If Mitigated
With proper memory limits and monitoring, impact is limited to FontForge application instability without affecting the host system.
🎯 Exploit Status
Exploitation requires crafting malicious font files and user interaction to open/process them. No known public exploits as of analysis.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Versions after the fix in GitHub PR #5491
Vendor Advisory: https://github.com/fontforge/fontforge/pull/5491
Restart Required: No
Instructions:
1. Update FontForge to latest version. 2. For v20230101, apply the patch from GitHub PR #5491. 3. Recompile if building from source. 4. Verify the fix by checking version or testing with known triggering conditions.
🔧 Temporary Workarounds
Avoid untrusted font processing
allRestrict FontForge to only process trusted font files from verified sources
Memory usage monitoring
allMonitor FontForge memory usage and restart if abnormal growth is detected
🧯 If You Can't Patch
- Isolate FontForge usage to dedicated systems with limited resources
- Implement strict file validation for all font files before processing
🔍 How to Verify
Check if Vulnerable:
Check FontForge version: if exactly v20230101, you are vulnerable. Also check if DlgCreate8 component exists in your build.Check Version:
fontforge --version 2>&1 | head -1Verify Fix Applied:
Update to latest version and test with previously problematic font files. Monitor memory usage during extended font processing sessions.📡 Detection & Monitoring
Log Indicators:
- FontForge crash logs
- Out of memory errors in system logs
- Abnormal memory consumption patterns
Network Indicators:
- N/A - local application vulnerability
SIEM Query:
process.name="fontforge" AND (event.action="crash" OR memory.usage>90%)