CVE-2025-13018
📋 TL;DR
This CVE describes a mitigation bypass vulnerability in the DOM Security component of Mozilla products. It allows attackers to circumvent security controls, potentially leading to arbitrary code execution. Affected users include those running vulnerable versions of Firefox, Firefox ESR, and Thunderbird.
💻 Affected Systems
- Firefox
- Firefox ESR
- Thunderbird
📦 What is this software?
Firefox by Mozilla
Firefox by Mozilla
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise via arbitrary code execution, potentially leading to data theft, ransomware deployment, or persistent backdoor installation.
Likely Case
Limited code execution within browser context, session hijacking, credential theft, or installation of malicious extensions.
If Mitigated
Minimal impact with proper network segmentation, application sandboxing, and up-to-date security controls.
🎯 Exploit Status
Exploitation requires user interaction (visiting malicious website or opening malicious email).
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Firefox 145+, Firefox ESR 140.5+, Thunderbird 145+, Thunderbird 140.5+
Vendor Advisory: https://www.mozilla.org/security/advisories/mfsa2025-87/
Restart Required: Yes
Instructions:
1. Open Firefox/Thunderbird. 2. Click menu → Help → About Firefox/Thunderbird. 3. Allow automatic update. 4. Restart when prompted. 5. Verify version is 145+ (Firefox) or 140.5+ (Firefox ESR/Thunderbird).
🔧 Temporary Workarounds
Disable JavaScript
allTemporarily disable JavaScript to prevent exploitation via malicious websites.
about:config → javascript.enabled = false
Use Content Security Policy
allImplement strict CSP headers to limit script execution.
Content-Security-Policy: script-src 'self'
🧯 If You Can't Patch
- Network segmentation: Isolate vulnerable systems from critical assets.
- Application control: Block execution of vulnerable browser versions via endpoint protection.
🔍 How to Verify
Check if Vulnerable:
Check browser version in About dialog or via command: firefox --version | thunderbird --versionCheck Version:
firefox --version 2>/dev/null || thunderbird --version 2>/dev/null || echo "Check via About menu"Verify Fix Applied:
Confirm version is Firefox ≥145, Firefox ESR ≥140.5, Thunderbird ≥145, or Thunderbird ≥140.5📡 Detection & Monitoring
Log Indicators:
- Unusual process spawn from browser
- Suspicious extension installation
- Multiple crash reports
Network Indicators:
- Connections to known malicious domains from browser process
- Unusual outbound traffic patterns
SIEM Query:
process_name:firefox.exe AND parent_process:explorer.exe AND cmdline:*suspicious*