CVE-2025-54143
📋 TL;DR
This vulnerability in Firefox for iOS allows sandboxed iframes to bypass download restrictions, enabling malicious websites to download files to devices without user consent. It affects Firefox for iOS versions below 141, putting mobile users at risk of malware installation or data theft.
💻 Affected Systems
- Firefox for iOS
📦 What is this software?
Firefox by Mozilla
⚠️ Risk & Real-World Impact
Worst Case
Attackers could download and execute malware, steal sensitive files, or compromise the entire iOS device through drive-by attacks on malicious websites.
Likely Case
Malicious websites could download unwanted files, adware, or tracking software to user devices without proper consent or security checks.
If Mitigated
With proper patching, the sandbox restrictions work as intended, preventing unauthorized downloads from iframes.
🎯 Exploit Status
Exploitation requires users to visit malicious websites but doesn't require authentication or special permissions.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 141
Vendor Advisory: https://www.mozilla.org/security/advisories/mfsa2025-60/
Restart Required: Yes
Instructions:
1. Open the App Store on iOS. 2. Search for Firefox. 3. Tap 'Update' if available. 4. Alternatively, uninstall and reinstall Firefox to get latest version.
🔧 Temporary Workarounds
Disable JavaScript in iframes
iosConfigure Firefox to block JavaScript execution in iframes, which may prevent exploitation but breaks many websites.
Use alternative browser
iosTemporarily switch to Safari or another browser until Firefox is updated.
🧯 If You Can't Patch
- Avoid visiting untrusted websites and use browser extensions that block malicious content
- Enable strict content security policies and disable automatic downloads in browser settings
🔍 How to Verify
Check if Vulnerable:
Open Firefox on iOS, go to Settings > About Firefox, check if version is below 141.Check Version:
Not applicable for iOS GUI app; check via Settings > About FirefoxVerify Fix Applied:
Confirm Firefox version is 141 or higher in Settings > About Firefox.📡 Detection & Monitoring
Log Indicators:
- Unexpected file downloads from web sources
- Iframe-related security violations in browser logs
Network Indicators:
- Unusual download traffic from web browsing sessions
- Requests bypassing sandbox policies
SIEM Query:
Not typically applicable for mobile browser vulnerabilities on personal devices