CVE-2026-2774
📋 TL;DR
An integer overflow vulnerability in Firefox's Audio/Video component could allow attackers to execute arbitrary code or cause denial of service. This affects Firefox versions below 148, Firefox ESR below 115.33, and Firefox ESR below 140.8. Users of these vulnerable versions are at risk when visiting malicious websites.
💻 Affected Systems
- Mozilla Firefox
- Mozilla 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 leading to complete system compromise, data theft, or ransomware deployment
Likely Case
Browser crash/denial of service, potential memory corruption leading to limited code execution
If Mitigated
Browser crash with no further impact if sandboxing and other security controls function properly
🎯 Exploit Status
Exploitation requires user interaction (visiting malicious website). No public exploit code available at this time.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: Firefox 148, Firefox ESR 115.33, Firefox ESR 140.8
Vendor Advisory: https://www.mozilla.org/security/advisories/mfsa2026-13/
Restart Required: Yes
Instructions:
1. Open Firefox. 2. Click menu → Help → About Firefox. 3. Firefox will automatically check for updates and install them. 4. Restart Firefox when prompted.
🔧 Temporary Workarounds
Disable Audio/Video Components
allTemporarily disable vulnerable audio/video processing features
about:config → media.webspeech.synth.enabled → false
about:config → media.webspeech.recognition.enabled → false
🧯 If You Can't Patch
- Restrict browser usage to trusted websites only
- Implement network filtering to block malicious content delivery
🔍 How to Verify
Check if Vulnerable:
Check Firefox version in menu → Help → About Firefox. If version is below 148 (or ESR below 115.33/140.8), system is vulnerable.Check Version:
firefox --versionVerify Fix Applied:
After update, verify version shows Firefox 148 or higher, or ESR 115.33/140.8 or higher.📡 Detection & Monitoring
Log Indicators:
- Browser crash logs with audio/video component errors
- Unexpected memory allocation failures in browser processes
Network Indicators:
- Unusual traffic to/from browser process
- Suspicious website visits preceding crashes
SIEM Query:
source="firefox.log" AND ("audio" OR "video") AND ("crash" OR "overflow" OR "memory")🔗 References
- https://bugzilla.mozilla.org/show_bug.cgi?id=2014883
- https://www.mozilla.org/security/advisories/mfsa2026-13/
- https://www.mozilla.org/security/advisories/mfsa2026-14/
- https://www.mozilla.org/security/advisories/mfsa2026-15/
- https://www.mozilla.org/security/advisories/mfsa2026-16/
- https://www.mozilla.org/security/advisories/mfsa2026-17/
