CVE-2026-24869
📋 TL;DR
A use-after-free vulnerability in Firefox's Layout: Scrolling and Overflow component allows attackers to execute arbitrary code by tricking users into visiting malicious web pages. This affects all Firefox users running versions below 147.0.2. Successful exploitation could lead to complete system compromise.
💻 Affected Systems
- Mozilla Firefox
📦 What is this software?
Firefox by Mozilla
⚠️ Risk & Real-World Impact
Worst Case
Remote code execution leading to full system compromise, data theft, and persistent backdoor installation.
Likely Case
Browser crash or limited code execution within the browser sandbox, potentially stealing session cookies and credentials.
If Mitigated
Browser crash with no code execution if sandboxing and exploit mitigations work effectively.
🎯 Exploit Status
Exploitation requires bypassing browser security mitigations like ASLR and sandboxing, but the vulnerability itself is accessible via web content.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 147.0.2
Vendor Advisory: https://www.mozilla.org/security/advisories/mfsa2026-06/
Restart Required: Yes
Instructions:
1. Open Firefox. 2. Click menu → Help → About Firefox. 3. Firefox will automatically check for updates and prompt to install version 147.0.2. 4. Restart Firefox when prompted.
🔧 Temporary Workarounds
Disable JavaScript
allPrevents exploitation by disabling JavaScript execution, which is required for most web-based attacks.
about:config → javascript.enabled → false
Use Content Security Policy
allImplement strict CSP headers to limit script execution from untrusted sources.
Content-Security-Policy: script-src 'self'
🧯 If You Can't Patch
- Restrict Firefox usage to trusted websites only using browser extensions or proxy rules.
- Implement application whitelisting to prevent unauthorized code execution from browser processes.
🔍 How to Verify
Check if Vulnerable:
Check Firefox version in About Firefox dialog. If version is less than 147.0.2, the system is vulnerable.Check Version:
firefox --versionVerify Fix Applied:
Confirm Firefox version is 147.0.2 or higher in About Firefox dialog.📡 Detection & Monitoring
Log Indicators:
- Firefox crash reports with memory corruption signatures
- Unexpected child process spawning from Firefox
Network Indicators:
- Connections to known malicious domains following browser crashes
- Unusual outbound traffic patterns from Firefox processes
SIEM Query:
process_name:"firefox.exe" AND (event_id:1000 OR event_id:1001) AND memory_corruption_signature