CVE-2026-0880
📋 TL;DR
This CVE describes an integer overflow vulnerability in the Graphics component of Mozilla products that allows sandbox escape. Attackers could exploit this to execute arbitrary code outside the browser's security sandbox. Affected users include anyone running vulnerable versions of Firefox, Firefox ESR, or Thunderbird.
💻 Affected Systems
- Firefox
- Firefox ESR
- Thunderbird
📦 What is this software?
Firefox by Mozilla
Firefox by Mozilla
Firefox by Mozilla
Thunderbird by Mozilla
Thunderbird by Mozilla
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise with attacker gaining complete control over the affected system, potentially leading to data theft, ransomware deployment, or persistent backdoor installation.
Likely Case
Arbitrary code execution with the privileges of the current user, enabling data exfiltration, credential theft, and lateral movement within the network.
If Mitigated
Limited impact due to sandboxing and other security controls, potentially resulting in only partial code execution or denial of service.
🎯 Exploit Status
Exploitation requires user interaction (visiting malicious website or opening malicious email), but no authentication is needed.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Firefox 147+, Firefox ESR 115.32+, Firefox ESR 140.7+, Thunderbird 147+, Thunderbird 140.7+
Vendor Advisory: https://www.mozilla.org/security/advisories/
Restart Required: Yes
Instructions:
1. Open Firefox/Thunderbird. 2. Click menu → Help → About Firefox/Thunderbird. 3. Allow automatic update download and installation. 4. Restart browser when prompted.
🔧 Temporary Workarounds
Disable JavaScript
allTemporarily disable JavaScript to prevent exploitation through 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 to isolate vulnerable systems
- Implement application allowlisting to prevent unauthorized code execution
🔍 How to Verify
Check if Vulnerable:
Check browser version against affected versions listCheck Version:
Firefox: about:support → Application Basics → Version. Thunderbird: Help → About ThunderbirdVerify Fix Applied:
Verify version is updated to patched versions listed in fix_official section📡 Detection & Monitoring
Log Indicators:
- Unusual process creation from browser processes
- Sandbox escape attempts in security logs
Network Indicators:
- Connections to known malicious domains from browser processes
- Unusual outbound traffic patterns
SIEM Query:
process_name="firefox.exe" AND (parent_process!="firefox.exe" OR integrity_level!="AppContainer")🔗 References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2005014
- https://www.mozilla.org/security/advisories/mfsa2026-01/
- https://www.mozilla.org/security/advisories/mfsa2026-02/
- https://www.mozilla.org/security/advisories/mfsa2026-03/
- https://www.mozilla.org/security/advisories/mfsa2026-04/
- https://www.mozilla.org/security/advisories/mfsa2026-05/
