CVE-2024-56519
📋 TL;DR
This vulnerability in TCPPDF allows cross-site scripting (XSS) attacks via malicious SVG files. Attackers can inject JavaScript through the font-family attribute in SVG content, which executes when the PDF is rendered. Any application using TCPPDF to process user-uploaded SVG files is affected.
💻 Affected Systems
- TCPDF
📦 What is this software?
Tcpdf by Tcpdf Project
⚠️ Risk & Real-World Impact
Worst Case
Full account compromise through session hijacking, credential theft, or malware delivery to users viewing malicious PDFs.
Likely Case
Limited XSS attacks stealing session cookies or performing actions as the victim user within the application context.
If Mitigated
No impact if SVG processing is disabled or proper input validation/sanitization is implemented.
🎯 Exploit Status
Exploitation requires user interaction (viewing malicious PDF) but no authentication. Simple SVG file creation needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 6.8.0
Vendor Advisory: https://github.com/tecnickcom/TCPDF/commit/c9f41cbb84880bdb4fc3e0a9d287214d1ac4d7f4
Restart Required: No
Instructions:
1. Update TCPDF to version 6.8.0 or later. 2. Replace existing TCPDF files with new version. 3. Test PDF generation functionality.
🔧 Temporary Workarounds
Disable SVG processing
allPrevent TCPDF from processing SVG content entirely
Configure application to not pass SVG content to TCPPDF
Input validation
allSanitize font-family attribute in SVG before processing
Implement regex filtering: preg_replace('/[^a-zA-Z0-9\s,\-]/', '', $fontFamily)
🧯 If You Can't Patch
- Implement strict Content Security Policy (CSP) headers to mitigate XSS impact
- Disable user SVG uploads or implement server-side SVG sanitization
🔍 How to Verify
Check if Vulnerable:
Check TCPDF version in code: grep -r 'TCPDF_VERSION' or check composer.json for version <6.8.0Check Version:
php -r "include('tcpdf.php'); echo TCPDF_VERSION;"Verify Fix Applied:
Verify version is 6.8.0+: echo TCPDF_VERSION; or check vendor/tecnickcom/tcpdf/tcpdf.php📡 Detection & Monitoring
Log Indicators:
- Unusual SVG file uploads
- PDF generation errors with SVG content
- Multiple failed SVG processing attempts
Network Indicators:
- HTTP requests with suspicious SVG content in POST data
- Unusual PDF download patterns
SIEM Query:
source="web_logs" AND (uri_path="*.svg" OR user_agent LIKE "%TCPDF%") AND status=200