CVE-2021-47840
📋 TL;DR
Moeditor 0.2.0 contains a persistent cross-site scripting (XSS) vulnerability where attackers can embed malicious JavaScript in markdown files. When victims open these specially crafted files, the JavaScript executes, potentially leading to remote code execution. This affects all users of Moeditor 0.2.0 who open untrusted markdown files.
💻 Affected Systems
- Moeditor
⚠️ Manual Verification Required
This CVE does not have specific version information in our database, so automatic vulnerability detection cannot determine if your system is affected.
Why? The CVE database entry doesn't specify which versions are vulnerable (no version ranges provided by the vendor/NVD).
🔒 Custom verification scripts are available for registered users. Sign up free to download automated test scripts.
- Review the CVE details at NVD
- Check vendor security advisories for your specific version
- Test if the vulnerability is exploitable in your environment
- Consider updating to the latest version as a precaution
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise via remote code execution, allowing attackers to install malware, steal data, or gain persistent access.
Likely Case
Session hijacking, credential theft, or limited system access through client-side attacks.
If Mitigated
No impact if proper input validation and output encoding are implemented, or if users only open trusted files.
🎯 Exploit Status
Exploit requires user interaction to open malicious markdown file. Proof of concept available in exploit databases.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Not available
Vendor Advisory: https://moeditor.js.org/
Restart Required: No
Instructions:
No official patch available. Consider upgrading to a newer version if available, or discontinue use of Moeditor 0.2.0.
🔧 Temporary Workarounds
Disable JavaScript execution in markdown files
allConfigure Moeditor to disable JavaScript execution when rendering markdown files.
Check Moeditor settings for 'Disable JavaScript' or similar option
Use alternative markdown editor
allReplace Moeditor 0.2.0 with a secure alternative markdown editor.
Uninstall Moeditor 0.2.0 and install alternative like Typora, VS Code, or Obsidian
🧯 If You Can't Patch
- Restrict Moeditor to opening only trusted, verified markdown files from known sources.
- Implement application whitelisting to prevent execution of unauthorized scripts from Moeditor.
🔍 How to Verify
Check if Vulnerable:
Check if Moeditor version is 0.2.0. Attempt to open a test markdown file containing <script>alert('XSS')</script> - if alert triggers, vulnerable.Check Version:
Check application About menu or run 'moeditor --version' in terminalVerify Fix Applied:
Test with same XSS payload - alert should not trigger. Verify Moeditor version is not 0.2.0.📡 Detection & Monitoring
Log Indicators:
- Unusual file access patterns to markdown files
- Multiple failed attempts to open corrupted markdown files
Network Indicators:
- Downloads of markdown files from untrusted sources
- Outbound connections from Moeditor to unknown IPs
SIEM Query:
Process:moeditor AND (FileExtension:.md OR FileExtension:.markdown) AND (CommandLine:*script* OR CommandLine:*javascript*)