CVE-2025-61656

N/A Unknown
Cross-Site Scripting

📋 TL;DR

This CVE describes a cross-site scripting (XSS) vulnerability in Wikimedia VisualEditor's clipboard handling component. It allows attackers to inject malicious scripts into web pages when users paste content, potentially affecting any user who interacts with VisualEditor on affected Wikimedia installations. The vulnerability impacts multiple versions of VisualEditor across Wikimedia deployments.

💻 Affected Systems

Products:
  • Wikimedia VisualEditor
Versions: VisualEditor before 1.39.14, 1.43.4, 1.44.1
Operating Systems: All
Default Config Vulnerable: ⚠️ Yes
Notes: Affects Wikimedia installations using VisualEditor component. The vulnerability is in the clipboard handling JavaScript file.

⚠️ Risk & Real-World Impact

🔴

Worst Case

Attackers could steal user session cookies, perform actions on behalf of authenticated users, deface content, or redirect users to malicious sites.

🟠

Likely Case

Attackers could inject malicious scripts that steal user data or perform limited unauthorized actions within the context of the affected user's session.

🟢

If Mitigated

With proper input validation and output encoding, the risk is reduced to minimal, though the vulnerability still exists in the codebase.

🌐 Internet-Facing: HIGH
🏢 Internal Only: MEDIUM

🎯 Exploit Status

Public PoC: ✅ No
Weaponized: UNKNOWN
Unauthenticated Exploit: ✅ No
Complexity: LOW

Exploitation requires user interaction (pasting content) but the technical complexity of crafting the exploit payload is low.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: VisualEditor 1.39.14, 1.43.4, or 1.44.1

Vendor Advisory: https://phabricator.wikimedia.org/T397232

Restart Required: No

Instructions:

1. Identify current VisualEditor version. 2. Upgrade to patched version (1.39.14, 1.43.4, or 1.44.1 depending on your branch). 3. Clear browser caches and verify the fix.

🔧 Temporary Workarounds

Disable VisualEditor clipboard features

all

Temporarily disable clipboard-related functionality in VisualEditor configuration

Modify LocalSettings.php: $wgVisualEditorEnableClipboard = false;

🧯 If You Can't Patch

  • Implement Content Security Policy (CSP) headers to restrict script execution
  • Enable input validation and output encoding at the application layer

🔍 How to Verify

Check if Vulnerable:

Check VisualEditor version in MediaWiki configuration or by examining the ve.Ce.ClipboardHandler.js file timestamp and content.

Check Version:

Check MediaWiki LocalSettings.php or use Special:Version page on the wiki.

Verify Fix Applied:

Verify VisualEditor version is 1.39.14, 1.43.4, or 1.44.1 or higher. Test clipboard paste functionality with test payloads.

📡 Detection & Monitoring

Log Indicators:

  • Unusual paste operations in VisualEditor logs
  • JavaScript errors related to clipboard handling

Network Indicators:

  • Unexpected script loads in VisualEditor requests
  • Suspicious content in POST data to editor endpoints

SIEM Query:

source="web_server" AND (uri_path="/w/load.php" OR uri_path="/api.php") AND (http_method="POST") AND (user_agent CONTAINS "VisualEditor")

📊 Metadata

CVE ID: CVE-2025-61656
CVSS v3 Score: N/A (Unknown)
CWE: CWE-79
Published: February 3, 2026
Last Updated: February 4, 2026

🤖 AI-assisted analysis, reviewed for accuracy

🔗 References

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