CVE-2026-2447
📋 TL;DR
A heap buffer overflow vulnerability in libvpx video codec library allows attackers to execute arbitrary code or cause denial of service. This affects Firefox browsers below specific versions across multiple release channels.
💻 Affected Systems
- Firefox
- Firefox ESR
📦 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
Remote code execution with the same privileges as the Firefox process, potentially leading to full system compromise.
Likely Case
Browser crash/denial of service, with potential for limited code execution in sandboxed environment.
If Mitigated
Browser crash with no code execution due to sandboxing and exploit mitigations.
🎯 Exploit Status
Heap buffer overflows typically require precise memory manipulation. No public exploit available at advisory time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Firefox 147.0.4, Firefox ESR 140.7.1, Firefox ESR 115.32.1
Vendor Advisory: https://www.mozilla.org/security/advisories/mfsa2026-10/
Restart Required: Yes
Instructions:
1. Open Firefox menu > Help > About Firefox. 2. Browser will check for updates automatically. 3. Click 'Restart to update Firefox' when prompted. 4. For enterprise deployments, use Firefox policy templates or deployment tools.
🔧 Temporary Workarounds
Disable VP8/VP9 video playback
allPrevents exploitation by disabling vulnerable codec
Set media.vp8.enabled to false in about:config
Set media.vp9.enabled to false in about:config
🧯 If You Can't Patch
- Restrict access to untrusted websites and video content
- Implement application whitelisting to prevent unauthorized code execution
🔍 How to Verify
Check if Vulnerable:
Check Firefox version in menu > Help > About FirefoxCheck Version:
firefox --version (Linux/macOS) or check About Firefox (Windows)Verify Fix Applied:
Verify version is 147.0.4 or higher (or ESR equivalent)📡 Detection & Monitoring
Log Indicators:
- Firefox crash reports with libvpx in stack trace
- Unexpected browser termination events
Network Indicators:
- Multiple requests to video files with malformed headers
SIEM Query:
source="firefox.logs" AND (event="crash" OR event="termination") AND process="firefox"