CVE-2025-14322: Mozilla Firefox Privilege Escalation Flaw

CVE-2025-14322 Overview

CVE-2025-14322 is a sandbox escape vulnerability affecting Mozilla Firefox and Thunderbird, caused by incorrect boundary conditions in the Graphics: CanvasWebGL component. This flaw allows attackers to escape the browser sandbox, potentially gaining unauthorized access to system resources beyond the browser's security boundary. The vulnerability requires user interaction and network access for exploitation but can result in significant confidentiality and integrity impacts.

Critical Impact

Successful exploitation allows attackers to escape the browser sandbox via maliciously crafted WebGL content, potentially compromising the underlying system beyond the browser's security constraints.

Affected Products

• Mozilla Firefox versions prior to 146
• Mozilla Firefox ESR versions prior to 115.31 and 140.6
• Mozilla Thunderbird versions prior to 146 and 140.6

Discovery Timeline

• December 9, 2025 - CVE-2025-14322 published to NVD
• April 13, 2026 - Last updated in NVD database

Technical Details for CVE-2025-14322

Vulnerability Analysis

This vulnerability resides in the Graphics: CanvasWebGL component of Mozilla Firefox and Thunderbird. The flaw stems from improper checking of exceptional conditions (CWE-754), specifically incorrect boundary condition handling when processing WebGL canvas operations. When the component fails to properly validate boundary conditions, it creates an opportunity for malicious content to escape the browser's sandbox environment.

The sandbox escape capability is particularly concerning as browser sandboxes are a critical security layer designed to isolate web content from the underlying operating system. By bypassing this protection, an attacker can potentially execute code with elevated privileges outside the browser's security context.

Root Cause

The root cause is improper checking of exceptional conditions (CWE-754) within the CanvasWebGL component's boundary validation logic. The component fails to properly handle edge cases when processing WebGL rendering operations, allowing malformed or specially crafted WebGL content to trigger memory operations that violate the sandbox's security boundaries.

Attack Vector

The attack requires network-based delivery of malicious content to a victim who must interact with the content (such as visiting a malicious webpage or opening a crafted email in Thunderbird). The attacker must craft WebGL content that exploits the incorrect boundary conditions, triggering the sandbox escape. While exploitation requires specific conditions to be met (high attack complexity), successful attacks can result in high confidentiality and integrity impacts on the target system.

The attack does not require authentication or prior privileges on the target system, and the scope change indicator means impacts can extend beyond the vulnerable component to affect other system resources.

Detection Methods for CVE-2025-14322

Indicators of Compromise

• Unusual WebGL canvas rendering activity or excessive GPU memory allocation in browser processes
• Browser processes attempting to access system resources outside normal sandbox permissions
• Unexpected child process spawning from Firefox or Thunderbird processes
• Anomalous network connections originating from browser processes after visiting untrusted sites

Detection Strategies

• Monitor for Firefox or Thunderbird processes exhibiting abnormal behavior such as accessing files or registry keys outside typical browser directories
• Deploy endpoint detection rules to identify sandbox escape attempts through anomalous parent-child process relationships
• Enable browser telemetry and crash reporting to identify potential exploitation attempts
• Implement network monitoring for suspicious WebGL-related traffic patterns

Monitoring Recommendations

• Enable enhanced logging for browser processes to capture potential sandbox violations
• Configure SentinelOne behavioral AI to detect post-exploitation activities following browser sandbox escapes
• Monitor for browser processes making unexpected system calls or accessing sensitive OS resources
• Review browser crash reports for patterns indicating exploitation attempts

How to Mitigate CVE-2025-14322

Immediate Actions Required

• Update Mozilla Firefox to version 146 or later immediately
• Update Firefox ESR to version 115.31 or 140.6 or later
• Update Mozilla Thunderbird to version 146 or 140.6 or later
• Verify all instances of Firefox and Thunderbird across the enterprise have been patched

Patch Information

Mozilla has released security patches addressing this vulnerability in multiple product versions. Detailed information is available in the following security advisories:

• Mozilla Security Advisory MFSA-2025-92
• Mozilla Security Advisory MFSA-2025-93
• Mozilla Security Advisory MFSA-2025-94
• Mozilla Security Advisory MFSA-2025-95
• Mozilla Security Advisory MFSA-2025-96

Technical details regarding the bug fix can be found in the Mozilla Bug Report #1996473.

Workarounds

• Disable WebGL in Firefox by navigating to about:config and setting webgl.disabled to true until patching is complete
• Restrict access to untrusted websites and limit browser usage to essential business functions
• Implement network-level blocking for known malicious domains serving exploit content
• Consider using browser isolation solutions to contain potential sandbox escape attempts

# Disable WebGL in Firefox via user.js configuration
# Add to Firefox profile directory user.js file:
echo 'user_pref("webgl.disabled", true);' >> /path/to/firefox/profile/user.js

# For enterprise deployment via policies.json:
# Create or modify /distribution/policies.json
cat << 'EOF' > /usr/lib/firefox/distribution/policies.json
{
  "policies": {
    "Preferences": {
      "webgl.disabled": {
        "Value": true,
        "Status": "locked"
      }
    }
  }
}
EOF