CVE-2026-102321 in Chrome
Summary
by MITRE • 09/29/2026
Type confusion in V8 in Google Chrome prior to 154.0.8037.92 allowed a remote attacker to execute arbitrary code inside the sandbox via a crafted HTML page. (Chromium security severity: High)
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Analysis
by VulDB Data Team • 09/29/2026
The vulnerability identified as a type confusion issue within the V8 JavaScript engine, which powers Google Chrome prior to version 154.0.8037.92, represents a critical failure in memory safety and runtime type checking mechanisms. Type confusions occur when an application incorrectly assumes that a variable or object holds one data type while it actually contains another. In the context of V8, this flaw allows for the manipulation of internal heap structures where objects are stored with specific metadata defining their shape and properties. When the engine fails to validate these types correctly during execution, it can lead to situations where an attacker-controlled value is treated as a different data structure than intended by the program logic. This discrepancy creates a pathway for memory corruption, specifically enabling arbitrary read or write operations within the JavaScript heap space.
From a technical perspective, this flaw exploits weaknesses in how V8 handles object shapes and hidden classes during Just-In-Time compilation and execution. The attacker crafts a malicious HTML page containing specific JavaScript code designed to trigger the type confusion condition. By carefully constructing objects with conflicting types and manipulating their properties through polymorphic inline caching or other optimization techniques, the adversary can cause the engine to misinterpret memory offsets. This misinterpretation allows for out-of-bounds reads or writes, which are fundamental prerequisites for achieving arbitrary code execution. The severity is classified as High because it directly impacts the integrity of the browser's core processing unit and serves as a reliable primitive for further exploitation steps such as sandbox escape.
The operational impact of this vulnerability is severe due to its potential for remote code execution via a crafted web page, which aligns with common attack vectors observed in modern cyber threats. An attacker does not need physical access or user interaction beyond visiting the malicious site, making it suitable for drive-by download attacks and targeted phishing campaigns. Once arbitrary code execution is achieved within the V8 sandbox, the immediate consequence is the compromise of the browser's security boundary. Although Chrome employs a multi-process architecture with sandboxes to limit damage, successful exploitation of this type confusion can potentially lead to sandbox escape techniques that grant the attacker higher privileges on the host system. This could result in full device compromise, data exfiltration, installation of persistent malware, or use as part of a larger botnet infrastructure.
This vulnerability maps directly to CWE-843, which describes access to incorrect type interpretation, and is closely related to CWE-120, buffer overflow without description of bounds, depending on the specific memory corruption mechanism triggered. In terms of offensive security frameworks like MITRE ATT&CK, this exploit falls under T1205.001, Trust Relationship Exploitation: Siphoning Trusted Information, and more broadly under initial access techniques that leverage browser vulnerabilities for code execution. The use of a crafted HTML page indicates an attack vector consistent with web-based delivery mechanisms often seen in advanced persistent threats seeking to exploit zero-day or recently patched flaws before widespread deployment of fixes occurs.
Mitigation strategies primarily involve the immediate application of vendor-provided patches, specifically upgrading Google Chrome to version 154.0.8037.92 or later where these type checking validations have been strengthened. For organizations managing large fleets of endpoints, automated patch management systems should be configured to prioritize browser updates due to the high severity and widespread usage of this software. Additionally, security teams can implement network-level controls such as web filtering proxies that inspect traffic for known exploit patterns associated with V8 vulnerabilities, although these are less effective against novel or obfuscated payloads. Endpoint detection and response solutions may also help identify suspicious behavior indicative of exploitation attempts, such as unusual memory allocation patterns or process spawning events originating from the browser executable.