CVE-2025-10201: Google Chrome Auth Bypass Vulnerability

CVE-2025-10201 Overview

CVE-2025-10201 is a high-severity vulnerability affecting Google Chrome's Mojo inter-process communication (IPC) subsystem. The flaw involves an inappropriate implementation that allows remote attackers to bypass Chrome's site isolation security mechanism through a specially crafted HTML page. Site isolation is a critical security boundary in Chrome designed to prevent malicious websites from accessing data from other sites, making this bypass particularly dangerous.

Critical Impact

Remote attackers can bypass site isolation protections in Google Chrome, potentially enabling cross-site data theft and undermining browser sandbox security on Android, Linux, and ChromeOS platforms.

Affected Products

• Google Chrome versions prior to 140.0.7339.127
• Google Chrome on Android
• Google Chrome on Linux
• Google Chrome on ChromeOS

Discovery Timeline

• September 10, 2025 - CVE-2025-10201 published to NVD
• September 22, 2025 - Last updated in NVD database

Technical Details for CVE-2025-10201

Vulnerability Analysis

This vulnerability is classified under CWE-284 (Improper Access Control), indicating a failure in properly enforcing access restrictions within Chrome's Mojo subsystem. Mojo serves as the primary IPC framework in Chromium, facilitating communication between browser processes, renderer processes, and various service components. The inappropriate implementation allows attackers to circumvent site isolation boundaries that are designed to keep web content from different origins separated in distinct processes.

Site isolation is a defense-in-depth security feature that ensures each website runs in its own dedicated process, preventing Spectre-style side-channel attacks and limiting the impact of renderer compromises. When site isolation is bypassed, an attacker-controlled page could potentially access sensitive data from other sites the user is logged into, including session tokens, cookies, and page content.

Root Cause

The vulnerability stems from an improper access control implementation within Chrome's Mojo IPC layer. The flaw allows boundary violations in how Mojo handles cross-process message routing or interface binding, enabling renderer processes to access data or interfaces they should not have permission to reach under normal site isolation constraints.

Attack Vector

The attack requires user interaction where the victim must navigate to a malicious webpage containing the crafted HTML payload. Once loaded, the attacker-controlled page exploits the Mojo implementation flaw to break out of its isolated process context. This network-based attack can be delivered through phishing links, malicious advertisements, or compromised websites.

The exploitation mechanism leverages the crafted HTML to trigger the inappropriate Mojo behavior, allowing the attacker's code to circumvent site isolation boundaries and potentially access cross-origin data. For detailed technical analysis, refer to the Chromium Issue Tracker Entry for this vulnerability.

Detection Methods for CVE-2025-10201

Indicators of Compromise

• Unusual Mojo IPC message patterns or cross-process interface binding attempts in Chrome crash reports
• Browser process crashes or instability related to site isolation failures
• Unexpected cross-origin data access attempts logged in browser diagnostic data

Detection Strategies

• Monitor for Chrome versions below 140.0.7339.127 across enterprise endpoints using asset management tools
• Implement browser version compliance policies that flag outdated Chrome installations
• Review crash dump data for Mojo-related exceptions that may indicate exploitation attempts

Monitoring Recommendations

• Enable Chrome's enhanced security telemetry to capture IPC anomalies
• Deploy endpoint detection solutions capable of monitoring browser process behavior
• Establish baseline Chrome version requirements and alert on non-compliant endpoints

How to Mitigate CVE-2025-10201

Immediate Actions Required

• Update Google Chrome to version 140.0.7339.127 or later immediately
• Enable automatic Chrome updates across all managed endpoints to prevent future delays
• Audit enterprise browser deployments to identify and remediate vulnerable versions

Patch Information

Google has addressed this vulnerability in Chrome version 140.0.7339.127. The fix resolves the inappropriate Mojo implementation that enabled the site isolation bypass. Organizations should refer to the Google Chrome Update Announcement for official patch details and deployment guidance. The update is available through Chrome's standard update mechanism on all affected platforms including Android, Linux, and ChromeOS.

Workarounds

• Use alternative browsers temporarily until Chrome can be updated on affected systems
• Restrict access to untrusted websites through URL filtering or content security policies
• Enable additional browser security features such as strict site isolation enforcement where configurable
• Consider blocking JavaScript execution on untrusted domains as a temporary risk reduction measure

# Verify Chrome version on Linux systems
google-chrome --version

# Force Chrome update check
google-chrome --check-for-update-interval=1

# Enterprise deployment: Set minimum required version policy
# In Chrome Enterprise policy configuration:
# MinimumChromeVersionEnforced: "140.0.7339.127"