CVE-2025-11152
📋 TL;DR
This CVE describes an integer overflow vulnerability in Firefox's Canvas2D graphics component that allows sandbox escape. Attackers could exploit this to execute arbitrary code outside the browser's security sandbox. All Firefox users running versions below 143.0.3 are affected.
💻 Affected Systems
- Mozilla Firefox
📦 What is this software?
Firefox by Mozilla
⚠️ Risk & Real-World Impact
Worst Case
Full system compromise through arbitrary code execution with user privileges, potentially leading to data theft, ransomware deployment, or persistent backdoor installation.
Likely Case
Malicious website could execute code on user's system, steal cookies/session data, install malware, or pivot to internal network resources.
If Mitigated
With proper browser sandboxing and least-privilege user accounts, impact limited to user-level access rather than system-wide compromise.
🎯 Exploit Status
Exploitation requires bypassing browser sandbox protections but integer overflow primitives are well-understood attack vectors.
🛠️ Fix & Mitigation
✅ Official Fix
Patch Version: 143.0.3
Vendor Advisory: https://www.mozilla.org/security/advisories/mfsa2025-80/
Restart Required: Yes
Instructions:
1. Open Firefox menu > Help > About Firefox. 2. Firefox will automatically check for updates. 3. If update available, click 'Restart to update Firefox'. 4. For enterprise deployments, use Firefox ESR or deploy via standard software distribution channels.
🔧 Temporary Workarounds
Disable Canvas2D via about:config
allTemporarily disable the vulnerable Canvas2D component
1. Type about:config in address bar
2. Search for 'canvas'
3. Set canvas.capturestream.enabled to false
4. Set canvas.filters.enabled to false
Use NoScript or similar extension
allBlock JavaScript execution on untrusted sites
Install NoScript extension from Firefox Add-ons
🧯 If You Can't Patch
- Restrict browser usage to trusted websites only using web filtering
- Implement application whitelisting to prevent unauthorized code execution
🔍 How to Verify
Check if Vulnerable:
Open Firefox > Help > About Firefox. If version is less than 143.0.3, system is vulnerable.Check Version:
firefox --version (Linux/macOS) or check Help > About Firefox (all platforms)Verify Fix Applied:
After update, verify version shows 143.0.3 or higher in About Firefox.📡 Detection & Monitoring
Log Indicators:
- Unusual Firefox crashes with memory access violations
- Multiple rapid Canvas API calls from single webpage
- Firefox child process spawning unexpected system processes
Network Indicators:
- HTTP requests to known exploit hosting domains
- Unusual outbound connections following browser use
SIEM Query:
source="firefox.log" AND ("canvas" OR "memory violation" OR "sandbox")