CVE-2025-66499
📋 TL;DR
A heap-based buffer overflow vulnerability in Foxit PDF Reader's JBIG2 image parsing allows remote code execution when opening malicious PDF files. This affects all users of vulnerable Foxit PDF Reader versions who open untrusted PDF documents. Attackers can exploit this to take control of affected systems.
💻 Affected Systems
- Foxit PDF Reader
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Remote attacker gains full system control with user privileges, enabling data theft, ransomware deployment, or persistent backdoor installation.
Likely Case
Targeted attacks against organizations via phishing emails with malicious PDF attachments leading to system compromise.
If Mitigated
Limited to denial of service or application crash if exploit fails or security controls block execution.
🎯 Exploit Status
Exploitation requires user interaction to open malicious PDF but no authentication. Integer overflow to buffer overflow chain requires precise control.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Check Foxit security bulletins for specific patched version
Vendor Advisory: https://www.foxit.com/support/security-bulletins.html
Restart Required: Yes
Instructions:
1. Visit Foxit security bulletins page
2. Identify affected version and download latest patch
3. Install update following vendor instructions
4. Restart system to complete installation
🔧 Temporary Workarounds
Disable JBIG2 image rendering
windowsConfigure Foxit PDF Reader to disable JBIG2 image processing via registry or configuration settings
Windows Registry: HKEY_CURRENT_USER\Software\Foxit Software\Foxit Reader\General\DisableJBIG2=1
Use alternative PDF viewer
allTemporarily use different PDF software until Foxit is patched
🧯 If You Can't Patch
- Block PDF files at network perimeter and email gateways
- Implement application whitelisting to prevent unauthorized PDF reader execution
🔍 How to Verify
Check if Vulnerable:
Check Foxit PDF Reader version against vulnerable versions listed in Foxit security advisoryCheck Version:
Windows: Open Foxit PDF Reader > Help > About; macOS: Foxit PDF Reader > About Foxit Reader; Linux: Check package manager or run 'foxitreader --version'Verify Fix Applied:
Verify installed version matches or exceeds patched version from Foxit advisory📡 Detection & Monitoring
Log Indicators:
- Application crashes of Foxit PDF Reader
- Unusual process creation from Foxit PDF Reader
- Memory access violation errors in system logs
Network Indicators:
- Inbound PDF files with JBIG2 images from untrusted sources
- Outbound connections from Foxit PDF Reader process to suspicious IPs
SIEM Query:
Process:foxitreader.exe AND (EventID:1000 OR ParentImage:cmd.exe OR CommandLine:*powershell*)