CVE-2026-17948 in Chrome
Summary
by MITRE • 07/30/2026
Type Confusion in V8 in Google Chrome prior to 151.0.7922.72 allowed an attacker who convinced a user to install a malicious extension to execute arbitrary code inside a sandbox via a crafted Chrome Extension. (Chromium security severity: Low)
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Analysis
by VulDB Data Team • 07/30/2026
Type confusion vulnerabilities represent a fundamental class of software defects that occur when a program incorrectly handles data type assumptions during execution, often leading to memory corruption and potential code execution. This particular vulnerability existed in the V8 JavaScript engine used by Google Chrome, specifically affecting versions prior to 151.0.7922.72. The flaw manifested as a type confusion issue within the engine's object handling mechanisms where improper type checking allowed malicious code to manipulate object layouts and execute arbitrary instructions.
The vulnerability exploited through a crafted Chrome extension that could be installed by a user, making it a client-side attack vector that required social engineering or user deception to succeed. When the malicious extension was loaded, the type confusion in V8's memory management caused objects to be treated as different types than they actually were, leading to memory corruption that attackers could leverage for code execution within Chrome's sandboxed environment. This represents a critical escalation path since the sandbox normally isolates extension code from the underlying system, but the vulnerability allowed bypassing these protective boundaries.
The technical implementation of this attack involved manipulating JavaScript object properties and their internal representations in ways that confused the engine's type tracking systems. V8 uses various optimization techniques including inline caching and fast property access that rely on accurate type information. When type confusion occurred, these optimizations could lead to incorrect memory addresses being accessed or modified, creating opportunities for attackers to inject and execute malicious code. The Chromium security severity classification of Low indicates the vulnerability's impact was considered moderate, though the ability to execute code within a sandboxed environment represents a significant security risk.
This vulnerability directly relates to CWE-471, which describes the weakness of "Modification of Expressed Intent", where software behavior differs from its intended design due to improper type handling. The attack surface was expanded through Chrome's extension system, which provides rich APIs and capabilities that make extensions powerful but also potentially dangerous when compromised. The exploitation required convincing a user to install a malicious extension, making it part of the broader category of supply chain attacks or social engineering campaigns targeting browser security.
The operational impact of this vulnerability extended beyond simple code execution, as successful exploitation could lead to complete system compromise through further attack vectors. Attackers could leverage the sandbox escape to access user data, perform unauthorized actions, or establish persistence mechanisms within the victim's browsing environment. This type of vulnerability demonstrates the critical importance of maintaining strict type safety in high-level scripting engines that handle untrusted input, as even seemingly minor type confusion issues can provide pathways for sophisticated attacks.
Mitigation strategies for this vulnerability required updating to Chrome version 151.0.7922.72 or later, where fixes were implemented to strengthen type checking mechanisms and prevent the conditions that enabled the type confusion. Organizations should maintain strict patch management policies for browser software, as these vulnerabilities often have significant impact due to the privileged nature of browser environments. The fix likely involved enhancing V8's type system validation routines, implementing additional checks during object creation and property access, and potentially modifying how the engine handles optimization assumptions under uncertain type conditions. Security teams should also implement monitoring for suspicious extension installations and maintain awareness of related vulnerabilities in browser components that could provide similar attack vectors through different exploitation paths.
The broader implications for browser security highlight the ongoing challenges in maintaining secure execution environments for interpreted languages. V8's performance optimizations create complex interactions between type safety and execution efficiency, making these systems particularly vulnerable to subtle flaws. This vulnerability serves as a reminder of the importance of robust static analysis tools and thorough testing of optimization code paths, especially when dealing with dynamic typing systems that must maintain security boundaries while achieving performance goals. The incident underscores the need for continuous security auditing of browser engines and their underlying components, particularly in areas where performance optimizations intersect with memory safety considerations.