CVE-2025-13023: Mozilla Firefox Privilege Escalation Flaw

CVE-2025-13023 Overview

CVE-2025-13023 is a critical sandbox escape vulnerability affecting Mozilla Firefox and Thunderbird. The flaw exists in the Graphics: WebGPU component due to incorrect boundary conditions, which can allow an attacker to escape the browser sandbox. WebGPU is a modern graphics API that provides low-level access to GPU hardware for high-performance rendering and computation. Due to improper boundary condition checks in this component, malicious web content could potentially break out of the browser's security sandbox and execute code with elevated privileges on the underlying system.

Critical Impact
This sandbox escape vulnerability could allow attackers to break out of browser isolation and potentially execute arbitrary code on the victim's system through malicious web content, compromising the entire security model of the browser.

Affected Products

Mozilla Firefox versions prior to 145
Mozilla Thunderbird versions prior to 145
Systems with WebGPU functionality enabled

Discovery Timeline

2025-11-11 - CVE-2025-13023 published to NVD
2025-11-19 - Last updated in NVD database

Technical Details for CVE-2025-13023

Vulnerability Analysis

This vulnerability is classified under CWE-703 (Improper Check or Handling of Exceptional Conditions). The flaw resides in the WebGPU graphics component, which handles low-level GPU operations for web content. The root issue stems from incorrect boundary condition validation when processing GPU-related operations, which can be exploited to escape the browser's sandbox protection mechanism.

WebGPU provides web applications with direct access to GPU capabilities for advanced graphics rendering and parallel computation. When boundary conditions are not properly validated in this component, attackers can craft malicious WebGPU operations that cause the browser to access memory outside of intended bounds. This can lead to corruption of sandbox control structures or direct execution of attacker-controlled code outside the sandbox context.

The attack requires no user interaction beyond visiting a malicious webpage, and no authentication or privileges are required to trigger the vulnerability. A successful exploit could result in complete compromise of confidentiality, integrity, and availability of the affected system.

Root Cause

The vulnerability originates from improper handling of boundary conditions within the WebGPU graphics component. When processing certain GPU operations, the code fails to properly validate input parameters against expected boundaries. This improper check allows malformed or specially crafted GPU commands to trigger memory access violations that can be leveraged to bypass sandbox restrictions. The CWE-703 classification indicates the component does not adequately check or handle exceptional conditions that arise during WebGPU processing.

Attack Vector

The attack is network-based, requiring the victim to visit a malicious webpage or receive malicious content through Thunderbird. An attacker would craft a webpage containing specially designed WebGPU API calls that exploit the boundary condition error. When the victim's browser processes this malicious WebGPU content, the incorrect boundary validation allows the attacker to manipulate memory in ways that bypass the sandbox. This could ultimately lead to arbitrary code execution on the victim's system outside of the browser's security constraints.

The vulnerability mechanism involves exploiting incorrect boundary checks in WebGPU operations. When the Graphics: WebGPU component processes certain operations, it fails to properly validate boundaries, allowing memory access outside intended ranges. This can be leveraged by attackers to corrupt sandbox control structures and escape the browser's isolation. For detailed technical information, see the Mozilla Bug Report #1992032 and Mozilla Security Advisory MFSA-2025-87.

Detection Methods for CVE-2025-13023

Indicators of Compromise

Unusual GPU process crashes or abnormal WebGPU API usage patterns in browser logs
Browser processes spawning unexpected child processes outside of normal operation
Memory access violations or segmentation faults in GPU-related processes
Abnormal network connections initiated from browser renderer processes

Detection Strategies

Monitor for WebGPU-related crashes or errors in browser diagnostic logs
Implement network security monitoring to detect exploitation attempts via malicious web content
Deploy endpoint detection solutions to identify sandbox escape behaviors and unusual process relationships
Review system logs for unexpected process creation from browser processes

Monitoring Recommendations

Enable enhanced logging for browser GPU processes and WebGPU operations
Configure security tools to alert on browser process anomalies and sandbox violations
Monitor for indicators of post-exploitation activity following browser compromise
Implement web content filtering to block known malicious domains targeting browser vulnerabilities

How to Mitigate CVE-2025-13023

Immediate Actions Required

Update Mozilla Firefox to version 145 or later immediately
Update Mozilla Thunderbird to version 145 or later immediately
Consider temporarily disabling WebGPU functionality if updates cannot be applied immediately
Review browser security configurations and enable available sandbox hardening options

Patch Information

Mozilla has released security patches addressing this vulnerability. Firefox users should update to version 145 or later, and Thunderbird users should update to version 145 or later. Security advisories with patch details are available at Mozilla Security Advisory MFSA-2025-87 and Mozilla Security Advisory MFSA-2025-90. Organizations should prioritize this update given the critical severity and sandbox escape nature of the vulnerability.

Workarounds

Disable WebGPU functionality in Firefox by navigating to about:config and setting dom.webgpu.enabled to false
Use browser isolation technologies to limit the impact of potential sandbox escapes
Implement network-level controls to restrict access to untrusted web content
Consider using application-level virtualization to contain browser processes

bash

# Firefox WebGPU disable configuration
# Navigate to about:config in Firefox and set:
# dom.webgpu.enabled = false

# Enterprise deployment via policies.json
# Place in Firefox installation directory/distribution/
cat << 'EOF' > /usr/lib/firefox/distribution/policies.json
{
  "policies": {
    "Preferences": {
      "dom.webgpu.enabled": {
        "Value": false,
        "Status": "locked"
      }
    }
  }
}
EOF