CVE-2025-15275
📋 TL;DR
A heap-based buffer overflow vulnerability in FontForge's SFD file parser allows remote attackers to execute arbitrary code when users open malicious files or visit malicious pages. This affects all FontForge installations that process SFD files, potentially compromising user systems.
💻 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 current user, leading to data theft, ransomware deployment, or persistent backdoor installation.
Likely Case
Local privilege escalation leading to user account compromise, data exfiltration, and lateral movement within the network.
If Mitigated
Application crash (denial of service) without code execution if exploit fails or protections like ASLR/DEP are effective.
🎯 Exploit Status
Exploitation requires user interaction (opening malicious file). The vulnerability is in ZDI's database but public exploit details are limited.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check FontForge official releases after CVE publication
Vendor Advisory: https://github.com/fontforge/fontforge/security/advisories
Restart Required: Yes
Instructions:
1. Check current FontForge version
2. Visit FontForge GitHub releases page
3. Download and install latest patched version
4. Restart system or application
🔧 Temporary Workarounds
Disable SFD file association
allPrevent automatic opening of SFD files with FontForge
Windows: assoc .sfd=
Linux: Remove .sfd MIME type association
macOS: Remove FontForge as default for .sfd files
Application sandboxing
allRun FontForge in restricted environment
Windows: Use AppLocker to restrict FontForge
Linux: Use Firejail or SELinux sandboxing
macOS: Use sandbox-exec
🧯 If You Can't Patch
- Implement strict file type filtering to block SFD files at network perimeter/email gateways
- Use endpoint protection with memory corruption detection and application control
🔍 How to Verify
Check if Vulnerable:
Check FontForge version and compare with patched releases from official repositoryCheck Version:
fontforge --versionVerify Fix Applied:
Verify installed version matches or exceeds patched version from vendor advisory📡 Detection & Monitoring
Log Indicators:
- FontForge crash logs with memory access violations
- Unexpected process spawning from FontForge
- Abnormal file access patterns for SFD files
Network Indicators:
- Downloads of suspicious SFD files from untrusted sources
- Unusual outbound connections from FontForge process
SIEM Query:
Process:fontforge AND (EventID:1000 OR ExceptionCode:c0000005) OR FileExtension:.sfd FROM untrusted_sources