CVE-2022-26486: Mozilla Firefox Use-After-Free Vulnerability

CVE-2022-26486 Overview

CVE-2022-26486 is a critical use-after-free vulnerability in the WebGPU Inter-Process Communication (IPC) framework used by Mozilla Firefox and related products. An unexpected message within this framework can trigger memory corruption that leads to an exploitable sandbox escape, allowing attackers to execute code outside the browser's security sandbox.

Critical Impact

This vulnerability has been actively exploited in the wild and is listed in CISA's Known Exploited Vulnerabilities catalog. The flaw enables attackers to bypass browser sandbox protections, potentially leading to full system compromise through malicious web content.

Affected Products

• Mozilla Firefox < 97.0.2
• Mozilla Firefox ESR < 91.6.1
• Mozilla Firefox for Android < 97.3.0
• Mozilla Thunderbird < 91.6.2
• Mozilla Firefox Focus < 97.3.0

Discovery Timeline

• 2022-12-22 - CVE-2022-26486 published to NVD
• 2025-11-04 - Last updated in NVD database

Technical Details for CVE-2022-26486

Vulnerability Analysis

This vulnerability resides in the WebGPU IPC framework, which facilitates communication between browser processes for GPU-accelerated graphics operations. The use-after-free condition (CWE-416) occurs when an unexpected message is processed, causing the framework to access memory that has already been freed.

WebGPU is designed to provide modern, low-level GPU access from web content, and its IPC layer manages resource sharing between the sandboxed content process and privileged GPU process. The improper handling of certain IPC messages creates a window where freed memory objects can be manipulated by an attacker.

The sandbox escape capability makes this vulnerability particularly severe, as successful exploitation allows code execution in the context of the parent browser process rather than the restricted content sandbox. This can lead to full browser compromise and potentially further system-level access depending on user privileges.

Root Cause

The root cause is improper memory management within the WebGPU IPC message handling code. When specific unexpected messages are received, the framework fails to properly validate object lifetimes before accessing them, leading to a use-after-free condition. This type of vulnerability typically occurs when:

1. An object is allocated and a pointer/reference is stored
2. The object is freed but the pointer/reference is not nullified
3. The dangling pointer is subsequently dereferenced, accessing freed memory

In this case, the IPC message processing pathway contains a race condition or logic flaw that allows message handlers to operate on resources that have been deallocated by another process or thread.

Attack Vector

The vulnerability is exploitable via network attack vector, requiring user interaction to visit a malicious website or open malicious content. An attacker can craft a web page containing JavaScript that triggers specific WebGPU IPC messages in an unexpected sequence. The attack flow involves:

1. Attacker hosts malicious content on a website or delivers it via email (for Thunderbird)
2. Victim navigates to the malicious page or opens malicious email content
3. JavaScript initiates WebGPU operations that generate the unexpected IPC messages
4. The use-after-free condition is triggered in the GPU process IPC handler
5. Attacker achieves code execution in the parent process, escaping the content sandbox

Due to confirmed active exploitation in the wild, detailed technical exploitation information has been restricted. Refer to the Mozilla Bug Report #1758070 for additional details as they become available.

Detection Methods for CVE-2022-26486

Indicators of Compromise

• Unexpected crashes or stability issues in Firefox, Thunderbird, or Firefox Focus processes
• Unusual child process spawning from browser processes indicating potential sandbox escape
• WebGPU-related error messages or warnings in browser console logs
• Evidence of exploitation attempts in network traffic targeting Mozilla browser users

Detection Strategies

• Monitor browser process hierarchies for anomalous parent-child relationships indicating sandbox violations
• Deploy endpoint detection solutions capable of identifying use-after-free exploitation patterns
• Implement network monitoring for known malicious infrastructure targeting this vulnerability
• Review system logs for evidence of code execution originating from browser processes

Monitoring Recommendations

• Enable enhanced logging for browser processes to capture WebGPU-related events
• Deploy memory corruption detection tools on endpoints where patching is delayed
• Monitor CISA KEV catalog updates for additional threat intelligence on active exploitation
• Correlate browser crash reports with security events to identify potential exploitation attempts

How to Mitigate CVE-2022-26486

Immediate Actions Required

• Update all affected Mozilla products to the latest patched versions immediately
• Prioritize updates for systems with internet-facing browser access
• Consider temporarily disabling WebGPU functionality if patches cannot be applied immediately
• Block known malicious domains associated with active exploitation campaigns

Patch Information

Mozilla has released security updates addressing this vulnerability. Apply the following minimum versions:

• Firefox 97.0.2 or later
• Firefox ESR 91.6.1 or later
• Firefox for Android 97.3.0 or later
• Thunderbird 91.6.2 or later
• Firefox Focus 97.3.0 or later

Detailed patch information is available in the Mozilla Security Advisory MFSA-2022-09. Organizations subject to CISA directives should note this vulnerability is listed in the CISA Known Exploited Vulnerabilities Catalog.

Workarounds

• Disable WebGPU functionality through browser configuration if immediate patching is not possible
• Implement browser isolation technologies to contain potential exploitation
• Use network-level controls to block access to untrusted websites on unpatched systems
• Consider using alternative browsers until patches can be applied to Mozilla products

# Firefox configuration to disable WebGPU (about:config)
# Set the following preference to false:
# dom.webgpu.enabled = false

# For enterprise deployments, add to policies.json:
# {
#   "policies": {
#     "Preferences": {
#       "dom.webgpu.enabled": false
#     }
#   }
# }