CVE-2025-12445
📋 TL;DR
A policy bypass vulnerability in Google Chrome extensions allows malicious extensions to leak cross-origin data. Attackers can exploit this by convincing users to install a crafted malicious extension. This affects Chrome users who install extensions from untrusted sources.
💻 Affected Systems
- Google Chrome
- Chromium-based browsers
📦 What is this software?
Chrome by Google
Google Chrome is the world's most popular web browser, used by over 3 billion users globally across Windows, macOS, Linux, Android, and iOS platforms. As a Chromium-based browser developed by Google, Chrome dominates the browser market with approximately 65% market share, making it a critical compon...
Learn more about Chrome →⚠️ Risk & Real-World Impact
Worst Case
Sensitive cross-origin data (like authentication tokens, session cookies, or private user data) could be exfiltrated to attacker-controlled servers.
Likely Case
Limited data leakage from websites the user visits, potentially exposing personal information or session data.
If Mitigated
With proper extension vetting and user awareness, impact is minimal as users must actively install malicious extensions.
🎯 Exploit Status
Exploitation requires social engineering to install malicious extension. No public exploit code is known.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 142.0.7444.59 and later
Vendor Advisory: https://chromereleases.googleblog.com/2025/10/stable-channel-update-for-desktop_28.html
Restart Required: Yes
Instructions:
Open Chrome
Click the three-dot menu → Help → About Google Chrome
Chrome will automatically check for and install updates
Click 'Relaunch' to restart Chrome with the update
🔧 Temporary Workarounds
Disable all extensions
allTemporarily disable all Chrome extensions to prevent exploitation
chrome://extensions/ → toggle off all extensions
Remove suspicious extensions
allReview and remove any extensions not from trusted sources
chrome://extensions/ → click 'Remove' on suspicious extensions
🧯 If You Can't Patch
- Only install extensions from the official Chrome Web Store
- Review and audit all installed extensions for suspicious behavior
🔍 How to Verify
Check if Vulnerable:
Check Chrome version in Settings → About Chrome. If version is below 142.0.7444.59, system is vulnerable.Check Version:
chrome://version/Verify Fix Applied:
Confirm Chrome version is 142.0.7444.59 or higher in Settings → About Chrome.📡 Detection & Monitoring
Log Indicators:
- Unusual extension installation events
- Extension permission changes
- Cross-origin data access attempts by extensions
Network Indicators:
- Unexpected outbound connections from Chrome to unknown domains
- Data exfiltration patterns from browser processes
SIEM Query:
process_name="chrome.exe" AND (event_id="ExtensionInstall" OR event_id="ExtensionPermissionChange")