CVE-2025-12380: Mozilla Firefox Use-After-Free Vulnerability

CVE-2025-12380 Overview

A critical use-after-free vulnerability exists in Mozilla Firefox versions 142 through 144.0.1, affecting the WebGPU implementation. Starting with Firefox 142, it was possible for a compromised child process to trigger a use-after-free condition in the GPU or browser process using WebGPU-related IPC (Inter-Process Communication) calls. This vulnerability may have been usable to escape the child process sandbox, potentially allowing an attacker to execute arbitrary code with elevated privileges outside the browser's security containment.

Critical Impact

This use-after-free vulnerability could enable sandbox escape, allowing attackers to break out of Firefox's security boundaries and potentially execute arbitrary code with elevated privileges on the host system.

Affected Products

• Mozilla Firefox versions 142.0 through 144.0.1
• Firefox installations with WebGPU functionality enabled
• All platforms running vulnerable Firefox versions (Windows, macOS, Linux)

Discovery Timeline

• 2025-10-28 - CVE-2025-12380 published to NVD
• 2025-12-19 - Last updated in NVD database

Technical Details for CVE-2025-12380

Vulnerability Analysis

This vulnerability is classified as CWE-416 (Use After Free), a memory corruption vulnerability that occurs when a program continues to reference memory after it has been freed. In the context of Firefox's WebGPU implementation, the flaw exists within the Inter-Process Communication (IPC) mechanism that facilitates communication between child processes (such as content processes or web workers) and the GPU or main browser process.

The WebGPU API provides high-performance graphics and compute capabilities to web applications. Firefox implements a multi-process architecture where web content runs in sandboxed child processes with limited privileges, while the GPU process handles graphics operations with elevated access. The IPC layer between these processes must carefully manage object lifetimes to prevent memory safety issues.

The vulnerability enables a compromised child process to manipulate WebGPU-related IPC messages in a way that causes the GPU or browser process to access memory that has already been deallocated. This creates a window for exploitation where an attacker can potentially control the contents of the freed memory region, leading to arbitrary code execution in the context of the privileged process.

Root Cause

The root cause stems from improper object lifecycle management in the WebGPU IPC handler code introduced in Firefox 142. When processing certain sequences of WebGPU-related IPC messages, the browser or GPU process fails to properly validate that referenced objects are still valid, allowing a malicious child process to trigger use of dangling pointers. This represents a failure in the reference counting or ownership tracking mechanisms that should prevent such conditions.

Attack Vector

The attack vector is network-based, requiring the attacker to first compromise a content process through a separate vulnerability (such as a renderer exploit via malicious web content). Once the content process is compromised, the attacker can craft malicious WebGPU IPC messages to trigger the use-after-free condition in the GPU or browser process. Successful exploitation would allow the attacker to escape the content process sandbox and execute code with the privileges of the browser or GPU process, effectively bypassing Firefox's multi-process security architecture.

The vulnerability requires no user interaction beyond visiting a malicious website and requires no special privileges, making it particularly dangerous when chained with a content process compromise. For detailed technical information, refer to the Mozilla Bug Report #1993113 and Mozilla Security Advisory MFSA-2025-86.

Detection Methods for CVE-2025-12380

Indicators of Compromise

• Unexpected crashes or instability in the Firefox GPU process (gpu-process) or main browser process
• Anomalous IPC message patterns in Firefox process logs, particularly WebGPU-related communications
• Evidence of memory corruption or heap manipulation in crash dumps
• Suspicious child process behavior attempting privileged operations outside sandbox boundaries
• Unusual network activity following Firefox browser usage indicating potential post-exploitation activity

Detection Strategies

• Monitor for Firefox browser crashes with signatures indicating use-after-free or heap corruption in WebGPU components
• Implement endpoint detection rules to identify attempts to escape browser sandbox boundaries
• Analyze crash telemetry for patterns consistent with exploitation attempts
• Deploy memory protection technologies that can detect heap corruption and use-after-free attempts
• Utilize SentinelOne's behavioral AI to identify anomalous process behavior indicative of sandbox escape

Monitoring Recommendations

• Enable Firefox crash reporting and monitor for patterns related to WebGPU or GPU process failures
• Configure endpoint protection to alert on suspicious process spawning from browser processes
• Monitor system calls from Firefox processes for attempts to access resources outside normal browser scope
• Track Firefox version deployment across the organization to identify vulnerable installations
• Implement network monitoring for unusual outbound connections following browser activity

How to Mitigate CVE-2025-12380

Immediate Actions Required

• Update Mozilla Firefox to version 144.0.2 or later immediately across all managed endpoints
• Prioritize patching for systems with high-risk exposure (public-facing, sensitive data access)
• Consider temporarily disabling WebGPU functionality via about:config setting dom.webgpu.enabled to false if immediate patching is not possible
• Ensure endpoint protection solutions are actively monitoring Firefox processes for suspicious behavior
• Review and remove any unauthorized Firefox installations running vulnerable versions

Patch Information

Mozilla has released Firefox version 144.0.2 to address this vulnerability. The patch corrects the object lifecycle management issues in the WebGPU IPC handler, ensuring proper validation of object references before use. Organizations should deploy this update through their standard software management processes. Details are available in Mozilla Security Advisory MFSA-2025-86.

Workarounds

• Disable WebGPU functionality by navigating to about:config and setting dom.webgpu.enabled to false
• Implement network-level controls to restrict access to potentially malicious websites
• Deploy browser isolation solutions to contain potential browser-based attacks
• Consider using alternative browsers temporarily until Firefox can be updated
• Enable strict site isolation if not already configured to limit content process capabilities

# Firefox WebGPU mitigation via user.js configuration
# Add to Firefox profile directory user.js file
user_pref("dom.webgpu.enabled", false);
user_pref("gfx.webgpu.force-enabled", false);

# Verify Firefox version via command line
firefox --version
# Expected output for patched version: Mozilla Firefox 144.0.2