CVE-2026-2768
📋 TL;DR
This CVE describes a sandbox escape vulnerability in Firefox's IndexedDB storage component. Attackers could potentially break out of browser security restrictions to execute arbitrary code. Affects Firefox versions below 148 and Firefox ESR versions below 140.8.
💻 Affected Systems
- Mozilla Firefox
- Mozilla Firefox ESR
📦 What is this software?
Firefox by Mozilla
Firefox by Mozilla
Thunderbird by Mozilla
Thunderbird by Mozilla
⚠️ Risk & Real-World Impact
Worst Case
Complete system compromise through arbitrary code execution with user privileges, potentially leading to data theft, ransomware deployment, or persistent backdoor installation.
Likely Case
Limited data exfiltration from browser storage, session hijacking, or installation of malicious browser extensions.
If Mitigated
Contained impact within browser process if proper sandboxing and privilege separation are maintained.
🎯 Exploit Status
Exploitation requires user to visit malicious website but no authentication needed. Sandbox escape vulnerabilities typically require chaining with other exploits for full impact.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Firefox 148, Firefox ESR 140.8
Vendor Advisory: https://www.mozilla.org/security/advisories/mfsa2026-13/
Restart Required: Yes
Instructions:
1. Open Firefox menu > Help > About Firefox. 2. Browser will automatically check for updates. 3. Click 'Restart to update Firefox' when prompted. 4. For enterprise deployments, use Firefox ESR and deploy version 140.8 or higher.
🔧 Temporary Workarounds
Disable JavaScript
allTemporarily disable JavaScript to prevent exploitation while patching
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
- Restrict browser usage to trusted websites only
- Implement application whitelisting to prevent unauthorized browser execution
🔍 How to Verify
Check if Vulnerable:
Check Firefox version in menu > Help > About Firefox. If version is below 148 (or below 140.8 for ESR), system is vulnerable.Check Version:
firefox --version (Linux/macOS) or check About Firefox (Windows)Verify Fix Applied:
After update, verify version shows 148 or higher (140.8 or higher for ESR) in About Firefox.📡 Detection & Monitoring
Log Indicators:
- Unusual IndexedDB access patterns
- Multiple failed sandbox policy violations
- Browser crash reports with memory corruption signatures
Network Indicators:
- Connections to known malicious domains after visiting suspicious sites
- Unusual outbound data transfers from browser process
SIEM Query:
source="firefox.log" AND ("IndexedDB" OR "sandbox") AND severity=CRITICAL