CVE-2025-8042
📋 TL;DR
Firefox for Android versions before 141 allow sandboxed iframes without the 'allow-downloads' attribute to initiate downloads, bypassing security restrictions. This affects all Firefox for Android users running vulnerable versions. Attackers can trick users into downloading malicious files through compromised websites.
💻 Affected Systems
- Firefox for Android
📦 What is this software?
Firefox by Mozilla
⚠️ Risk & Real-World Impact
Worst Case
Attackers download and execute malware, ransomware, or spyware onto the device, leading to complete system compromise, data theft, or financial loss.
Likely Case
Users download malicious files (e.g., fake apps, documents with malware) that could lead to credential theft, adware installation, or device performance issues.
If Mitigated
With proper controls like updated browsers and security software, downloads are blocked or flagged as suspicious, minimizing damage.
🎯 Exploit Status
Exploitation requires tricking users into visiting a malicious website with a crafted iframe. No authentication needed, making it easy to weaponize.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Firefox for Android 141
Vendor Advisory: https://www.mozilla.org/security/advisories/mfsa2025-56/
Restart Required: Yes
Instructions:
1. Open Google Play Store. 2. Search for Firefox. 3. Tap Update to version 141 or later. 4. Restart Firefox after update.
🔧 Temporary Workarounds
Disable JavaScript in Firefox for Android
androidPrevents iframes from executing malicious scripts that trigger downloads.
Open Firefox > Settings > Advanced > Enable JavaScript (toggle off)
Use Alternative Browser
androidSwitch to a non-vulnerable browser until Firefox is updated.
Install Chrome, Edge, or other browsers from Google Play Store
🧯 If You Can't Patch
- Avoid visiting untrusted websites or clicking suspicious links.
- Enable device security features like Google Play Protect to scan downloads.
🔍 How to Verify
Check if Vulnerable:
Open Firefox for Android > Settings > About Firefox. If version is less than 141, it is vulnerable.Check Version:
Not applicable for Android GUI; use Settings > About Firefox.Verify Fix Applied:
After updating, check version in About Firefox; confirm it is 141 or higher.📡 Detection & Monitoring
Log Indicators:
- Unexpected download events in Firefox logs
- Multiple download attempts from iframe sources
Network Indicators:
- HTTP requests for file downloads originating from iframe domains
- Suspicious download URLs in network traffic
SIEM Query:
Not typically applicable for mobile browsers; monitor for anomalies in web proxy logs related to Firefox user-agent and download patterns.