CVE-2020-7750
📋 TL;DR
CVE-2020-7750 is a DOM-based cross-site scripting (XSS) vulnerability in scratch-svg-renderer where improper SVG escaping allows attackers to inject arbitrary HTML elements. This affects applications using vulnerable versions of the scratch-svg-renderer package to process SVG content. Users who load untrusted SVG files through affected versions are at risk.
💻 Affected Systems
- scratch-svg-renderer
📦 What is this software?
⚠️ Risk & Real-World Impact
Worst Case
Full account takeover via session hijacking, credential theft, or malware delivery to users through malicious SVG files.
Likely Case
Limited XSS attacks stealing user data or performing actions within the user's context on the affected application.
If Mitigated
No impact if proper content security policies (CSP) are enforced and SVG input is sanitized.
🎯 Exploit Status
Exploitation requires user interaction to load malicious SVG content, but no authentication is needed for the XSS payload execution.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 0.2.0-prerelease.20201019174008 and later
Vendor Advisory: https://github.com/LLK/scratch-svg-renderer/commit/9ebf57588aa596c4fa3bb64209e10ade395aee90
Restart Required: No
Instructions:
1. Update package.json to use scratch-svg-renderer version 0.2.0-prerelease.20201019174008 or later. 2. Run npm update scratch-svg-renderer. 3. Rebuild and redeploy your application.
🔧 Temporary Workarounds
Input Sanitization
allImplement server-side sanitization of SVG content before passing to scratch-svg-renderer.
Content Security Policy
allEnforce strict CSP headers to block inline script execution.
🧯 If You Can't Patch
- Disable SVG rendering functionality in affected applications
- Implement network-level filtering to block SVG file uploads
🔍 How to Verify
Check if Vulnerable:
Check package.json or node_modules/scratch-svg-renderer/package.json for version number.Check Version:
npm list scratch-svg-rendererVerify Fix Applied:
Confirm version is 0.2.0-prerelease.20201019174008 or later and test SVG rendering with known malicious payloads.📡 Detection & Monitoring
Log Indicators:
- Unusual SVG file uploads
- JavaScript execution errors from SVG parsing
Network Indicators:
- SVG files containing script tags or JavaScript URIs
SIEM Query:
source="web_logs" AND (uri="*.svg" OR content="<script" OR content="javascript:")