CVE-2025-7656: Google Chrome V8 RCE Vulnerability

CVE-2025-7656 Overview

CVE-2025-7656 is an integer overflow vulnerability in the V8 JavaScript engine used by Google Chrome. This vulnerability exists in Chrome versions prior to 138.0.7204.157 and allows a remote attacker to potentially exploit heap corruption via a crafted HTML page. The vulnerability is classified with a Chromium security severity of High.

Critical Impact

Remote attackers can exploit this integer overflow to trigger heap corruption, potentially leading to arbitrary code execution within the browser context through maliciously crafted web content.

Affected Products

• Google Chrome versions prior to 138.0.7204.157

Discovery Timeline

• 2025-07-15 - CVE-2025-7656 published to NVD
• 2025-07-16 - Last updated in NVD database

Technical Details for CVE-2025-7656

Vulnerability Analysis

This vulnerability stems from an integer overflow condition within the V8 JavaScript engine, which is the core component responsible for executing JavaScript code in Google Chrome. Integer overflows occur when an arithmetic operation attempts to create a numeric value that exceeds the range that can be represented within the allocated number of bits.

In the context of V8, this integer overflow can lead to heap corruption. When the overflow occurs, it may cause the engine to allocate insufficient memory for data structures, or miscalculate array bounds, resulting in out-of-bounds memory access. This heap corruption can be weaponized by attackers to achieve arbitrary code execution.

The vulnerability requires user interaction—specifically, the victim must navigate to a malicious webpage containing the crafted HTML and JavaScript payload. Once triggered, the compromised V8 engine could allow attackers to execute arbitrary code with the privileges of the browser process.

Root Cause

The root cause is an integer overflow condition in V8's internal arithmetic operations. When processing specially crafted JavaScript or HTML content, numeric calculations within V8 can exceed the maximum value representable by the integer type used, causing the value to wrap around. This arithmetic error subsequently causes incorrect memory allocation sizes or buffer boundaries, leading to heap corruption conditions.

Attack Vector

The attack vector is network-based, requiring no prior authentication or privileges. An attacker must craft a malicious HTML page containing JavaScript code designed to trigger the integer overflow condition in V8. The attack sequence involves:

1. The attacker hosts or injects malicious HTML content on a website
2. The victim navigates to the malicious page using a vulnerable version of Google Chrome
3. The crafted JavaScript triggers the integer overflow in V8
4. The resulting heap corruption enables further exploitation, potentially leading to code execution

The vulnerability mechanism involves numeric overflow conditions in V8's JavaScript processing pipeline. When the engine performs arithmetic operations on attacker-controlled values, insufficient bounds checking allows integer values to overflow, corrupting heap metadata or adjacent memory structures. For detailed technical analysis, refer to the Chromium Issue Tracker Entry.

Detection Methods for CVE-2025-7656

Indicators of Compromise

• Unusual browser crashes or hangs when visiting specific websites
• Unexpected child processes spawned by Chrome browser processes
• Memory access violations or heap corruption signatures in crash dumps
• Network connections to suspicious domains from browser processes

Detection Strategies

• Monitor for Chrome versions older than 138.0.7204.157 across the enterprise using asset management tools
• Deploy browser-based anomaly detection to identify unusual JavaScript execution patterns
• Analyze crash reports for V8-related heap corruption indicators
• Implement web content filtering to block known malicious domains

Monitoring Recommendations

• Enable Chrome's built-in crash reporting and review crash patterns for V8-related issues
• Utilize endpoint detection and response (EDR) solutions to monitor browser process behavior
• Review proxy and firewall logs for connections to suspicious or newly registered domains
• Implement browser version tracking and alerting for outdated installations

How to Mitigate CVE-2025-7656

Immediate Actions Required

• Update Google Chrome to version 138.0.7204.157 or later immediately
• Enable automatic Chrome updates across the organization
• Consider using enterprise browser management tools to enforce version compliance
• Educate users about the risks of visiting untrusted websites until patching is complete

Patch Information

Google has addressed this vulnerability in Chrome version 138.0.7204.157. Organizations should prioritize updating all Chrome installations to this version or later. For detailed information about the security update, refer to the Google Chrome Update Announcement.

The update includes fixes for the integer overflow condition in V8 that enables heap corruption exploitation.

Workarounds

• Restrict access to untrusted websites using web filtering solutions until patches can be deployed
• Consider enabling Site Isolation features if not already enabled (chrome://flags/#enable-site-per-process)
• Implement network-level controls to filter potentially malicious web content
• Use browser virtualization or sandboxing solutions for high-risk browsing activities

# Check Chrome version via command line (Windows)
# Navigate to chrome://version in browser or run:
reg query "HKLM\SOFTWARE\Google\Chrome\BLBeacon" /v version

# Linux: Check Chrome version
google-chrome --version

# macOS: Check Chrome version
/Applications/Google\ Chrome.app/Contents/MacOS/Google\ Chrome --version