CVE-2026-4680: Google Chrome Use After Free Vulnerability

CVE-2026-4680 Overview

CVE-2026-4680 is a use-after-free vulnerability affecting the Federated Credential Management (FedCM) API in Google Chrome prior to version 146.0.7680.165. This memory corruption flaw enables remote attackers to potentially execute arbitrary code inside Chrome's sandbox by enticing a victim to visit a specially crafted HTML page. The vulnerability affects Chrome installations across all major desktop platforms including Windows, macOS, and Linux.

Critical Impact
Remote code execution within Chrome's sandbox through malicious web content targeting the FedCM authentication API

Affected Products

Google Chrome prior to version 146.0.7680.165
Chrome on Microsoft Windows
Chrome on Apple macOS
Chrome on Linux

Discovery Timeline

March 24, 2026 - CVE-2026-4680 published to NVD
March 24, 2026 - Last updated in NVD database

Technical Details for CVE-2026-4680

Vulnerability Analysis

CVE-2026-4680 is classified as a use-after-free vulnerability (CWE-416) residing in Google Chrome's Federated Credential Management (FedCM) implementation. FedCM is a browser API designed to facilitate privacy-preserving federated authentication workflows, allowing users to sign in to websites using identity providers without third-party cookies.

The vulnerability occurs when memory that has been freed is subsequently accessed during FedCM operations. This temporal memory safety violation can lead to undefined behavior, with attackers able to craft malicious HTML content that triggers the dangling pointer condition. While successful exploitation is constrained by Chrome's sandbox architecture, the ability to execute code within the renderer process represents a significant security risk, particularly when combined with sandbox escape vulnerabilities.

Root Cause

The root cause stems from improper memory management within the FedCM component. Specifically, an object is deallocated while references to it remain active in the code path. When these stale references are subsequently dereferenced, the browser accesses memory that may have been reallocated for different purposes, enabling an attacker to manipulate program execution flow through heap grooming techniques.

Attack Vector

The attack vector is network-based and requires user interaction—specifically, the victim must navigate to an attacker-controlled webpage or be redirected to malicious content. The crafted HTML page triggers the vulnerable code path in the FedCM API, exploiting the use-after-free condition.

An attacker would typically:

Host a malicious webpage containing crafted HTML and JavaScript that interacts with the FedCM API
Lure the victim to visit the page through phishing, malvertising, or watering hole attacks
Trigger the use-after-free condition through specific API call sequences
Achieve arbitrary code execution within the Chrome renderer sandbox

Technical details regarding the specific exploitation mechanism can be found in the Chromium Issue Tracker #491869946.

Detection Methods for CVE-2026-4680

Indicators of Compromise

Unusual crash reports from Chrome's renderer process related to FedCM components
Unexpected FedCM API calls in browser logs or network traffic
Memory corruption signatures or heap spray patterns in crash dumps
Suspicious JavaScript attempting to interact with credential management APIs

Detection Strategies

Monitor for Chrome process crashes with memory corruption signatures, particularly in renderer processes
Implement Content Security Policy (CSP) headers to restrict potentially malicious script execution
Deploy endpoint detection solutions capable of identifying browser-based exploitation attempts
Analyze web proxy logs for traffic patterns consistent with exploit delivery pages

Monitoring Recommendations

Enable Chrome's crash reporting to collect telemetry on renderer process failures
Monitor enterprise browser deployments for version compliance below 146.0.7680.165
Implement network-level detection for known exploit delivery domains
Review browser extension activity for suspicious interactions with authentication APIs

How to Mitigate CVE-2026-4680

Immediate Actions Required

Update Google Chrome to version 146.0.7680.165 or later immediately across all systems
Enable automatic Chrome updates if not already configured
Conduct an inventory of Chrome installations to identify vulnerable versions
Consider temporarily restricting access to untrusted websites until patching is complete

Patch Information

Google has addressed this vulnerability in Chrome version 146.0.7680.165. The security update is available through Chrome's automatic update mechanism and via direct download from Google. For detailed patch information, refer to the Google Chrome Desktop Update announcement.

Organizations using managed Chrome deployments should push the updated version through their enterprise management tools. The Chromium project has assigned this issue a High severity rating.

Workarounds

If immediate patching is not possible, consider using an alternative browser temporarily for sensitive operations
Implement network-level filtering to block access to known malicious domains
Enable Chrome's Site Isolation feature if not already active to limit cross-origin attack surface
Deploy browser security extensions that provide additional protection against malicious scripts

bash

# Verify Chrome version on Linux/macOS
google-chrome --version

# Force Chrome update check (user-initiated)
# Navigate to: chrome://settings/help

# Enterprise deployment: Check Chrome version via policy
# Verify minimum version requirement of 146.0.7680.165