CVE-2026-3923: Google Chrome WebMIDI Use After Free Flaw

CVE-2026-3923 Overview

A use-after-free vulnerability has been discovered in the WebMIDI component of Google Chrome prior to version 146.0.7680.71. This memory corruption flaw allows a remote attacker to potentially exploit heap corruption through a specially crafted HTML page, enabling arbitrary code execution within the browser context.

Critical Impact
Successful exploitation of this use-after-free vulnerability could allow attackers to execute arbitrary code, steal sensitive information, or compromise the affected system through heap corruption when users visit malicious web pages.

Affected Products

Google Chrome prior to version 146.0.7680.71
Chromium-based browsers using vulnerable WebMIDI implementation
All platforms running affected Chrome versions (Windows, macOS, Linux)

Discovery Timeline

2026-03-11 - CVE-2026-3923 published to NVD
2026-03-12 - Last updated in NVD database

Technical Details for CVE-2026-3923

Vulnerability Analysis

This vulnerability is classified as CWE-416 (Use After Free), a memory corruption flaw that occurs when a program continues to reference memory after it has been freed. In the context of the WebMIDI API implementation within Google Chrome, this vulnerability arises when handling MIDI device interactions through the browser's Web MIDI API interface.

The WebMIDI API provides web applications with the ability to communicate with MIDI (Musical Instrument Digital Interface) devices. When processing MIDI messages or managing MIDI port connections, improper memory management can result in dangling pointer references. An attacker can craft a malicious HTML page that triggers specific sequences of MIDI operations, causing the browser to access freed heap memory.

The network-based attack vector requires user interaction—specifically, a victim must navigate to or be redirected to an attacker-controlled webpage. Once triggered, the heap corruption can potentially be leveraged to achieve arbitrary code execution within the renderer process sandbox.

Root Cause

The root cause stems from improper lifecycle management of MIDI-related objects within the WebMIDI implementation. When MIDI port objects or message handlers are freed but references to these objects persist elsewhere in the code, subsequent operations can access the deallocated memory. This dangling pointer condition creates an exploitable use-after-free scenario where attacker-controlled data may be placed in the freed memory region, potentially allowing control flow hijacking.

Attack Vector

The attack is conducted remotely over the network by enticing a user to visit a malicious webpage. The attacker embeds JavaScript code that interacts with the WebMIDI API in a specific manner designed to trigger the use-after-free condition. This typically involves:

Requesting access to MIDI devices through the Web MIDI API
Creating and manipulating MIDI port connection objects
Triggering specific timing conditions that cause premature object deallocation
Accessing the freed memory through retained references to corrupt heap structures

The vulnerability affects the browser's renderer process, which operates within Chrome's sandbox. However, successful heap corruption could potentially be chained with additional vulnerabilities to escape the sandbox or be used for information disclosure attacks.

Detection Methods for CVE-2026-3923

Indicators of Compromise

Unusual browser crashes or instability when visiting specific websites
Unexpected MIDI permission prompts on websites that shouldn't require MIDI access
Memory corruption errors or heap-related crashes in Chrome crash reports
Suspicious JavaScript code making extensive WebMIDI API calls

Detection Strategies

Monitor browser crash reports for patterns indicating heap corruption in WebMIDI components
Deploy web content filtering to block known malicious pages exploiting this vulnerability
Implement endpoint detection rules to identify suspicious WebMIDI API usage patterns
Enable browser telemetry to detect anomalous MIDI permission requests

Monitoring Recommendations

Review Chrome browser versions across the enterprise to identify unpatched installations
Monitor network traffic for indicators of malicious page delivery targeting this vulnerability
Enable enhanced crash reporting to identify potential exploitation attempts
Track WebMIDI API permission grants for unusual activity patterns

How to Mitigate CVE-2026-3923

Immediate Actions Required

Update Google Chrome to version 146.0.7680.71 or later immediately
Enable automatic Chrome updates across all managed endpoints
Review and audit installed browser versions organization-wide
Consider temporarily disabling WebMIDI API access if immediate patching is not possible

Patch Information

Google has released a security update addressing this vulnerability in Chrome version 146.0.7680.71. The fix resolves the use-after-free condition in the WebMIDI implementation by implementing proper memory lifecycle management. Organizations should prioritize deploying this update across all endpoints.

For detailed information about the security update, refer to the Google Chrome Stable Update announcement. Additional technical details may be available in the Chromium Issue Tracker entry.

Workarounds

Block access to untrusted websites through web content filtering
Disable the WebMIDI API via Chrome enterprise policies if MIDI functionality is not required
Implement browser isolation solutions for high-risk browsing activities
Use network-level protections to prevent access to known malicious domains

bash

# Chrome enterprise policy to disable WebMIDI API (Windows Registry)
# HKEY_LOCAL_MACHINE\SOFTWARE\Policies\Google\Chrome
# DefaultMidiSetting = 2 (Block MIDI access)

# For managed Chrome deployments, add to policy JSON:
# {
#   "DefaultMidiSetting": 2
# }