Microsoft Edge Under Attack: Unpacking CVE-2025-49713's Type Confusion Exploit

Introduction

A critical security flaw in Microsoft Edge, CVE-2025-49713, has surfaced, actively exploited by attackers to execute arbitrary code remotely. This type confusion vulnerability, rooted in the browser's V8 JavaScript engine, underscores the persistent threats facing Chromium-based browsers and highlights the urgency for immediate patching.

Technical Information

Vulnerability Mechanics

CVE-2025-49713 involves a type confusion issue (CWE-843) within the V8 JavaScript engine's Just-In-Time (JIT) compilation process. Specifically, the engine fails to properly validate object types during memory operations. Attackers exploit this flaw by crafting malicious JavaScript that triggers improper type handling, leading to memory corruption and arbitrary code execution.

Attack Vectors and Exploitation Methods

Exploitation typically requires user interaction, such as visiting a maliciously crafted webpage. Once accessed, the malicious JavaScript triggers type confusion during the JIT optimization phase, corrupting memory and allowing attackers to execute arbitrary code within the browser's renderer process. This can subsequently lead to sandbox escapes and full system compromise.

Patch Information

Microsoft has released a security update for Microsoft Edge to address multiple vulnerabilities, including CVE-2025-6554, which is known to be exploited in the wild. This update is available in Microsoft Edge version 138.0.3351.65 and later. Users are strongly advised to update their browsers to this version to mitigate potential risks.

To update Microsoft Edge, navigate to the browser's menu, select 'Help and Feedback,' then 'About Microsoft Edge.' The browser will automatically check for updates and prompt you to restart if an update is available.

Affected Systems and Versions

Microsoft Edge versions prior to 138.0.3351.65
Chromium versions prior to 138.0.7151.69
Other Chromium-based browsers utilizing the V8 JavaScript engine

Vendor Security History

Microsoft has a history of addressing type confusion vulnerabilities in Edge, reflecting ongoing challenges with the V8 engine. The vendor typically demonstrates rapid response times, often releasing patches within days of vulnerability disclosure. However, the frequency of such vulnerabilities highlights persistent risks associated with Chromium-based browsers.