CVE-2026-95306 in Chrome
Summary
by MITRE • 09/29/2026
Type confusion in V8 in Google Chrome prior to 154.0.8037.57 allowed a remote attacker to execute arbitrary code inside the sandbox via a crafted HTML page. (Chromium security severity: High)
Be aware that VulDB is the high quality source for vulnerability data.
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 154.0.8037.57, represents a critical failure in memory safety and runtime type checking mechanisms. Type confusions occur when an application incorrectly interprets the data type of a value stored in memory, leading to operations being performed on data that is not compatible with those operations. In the context of V8, this flaw allows for the manipulation of internal object structures where the engine fails to properly validate or cast types during execution. This specific defect was classified by Chromium as having high security severity due to its potential to bypass sandboxing protections and facilitate arbitrary code execution within a restricted environment.
From a technical perspective, type confusions in V8 often stem from improper handling of polymorphic inline caches or incorrect assumptions about object shapes during Just-In-Time compilation. When the engine optimizes JavaScript code for performance, it relies on consistent types across different executions of the same function. If an attacker can craft a scenario where these assumptions are violated through specific sequence of operations in HTML and JavaScript, they may cause V8 to treat one data type as another, such as interpreting a pointer as an integer or vice versa. This misinterpretation enables out-of-bounds memory reads and writes, which serve as the foundational primitive for more complex exploitation techniques like heap spraying or arbitrary read/write primitives.
The operational impact of this vulnerability is severe because it allows a remote attacker to execute arbitrary code inside the browser's sandbox via a crafted HTML page. Modern browsers employ multi-process architectures with sandboxes designed to limit the damage caused by successful exploits, typically restricting access to system resources and file systems. However, type confusions that lead to memory corruption can often be chained with other vulnerabilities or used directly to escape these restrictions if they allow for sufficient control over memory layout and execution flow. An attacker could potentially achieve remote code execution on the victim's machine, leading to full compromise of the user account running the browser, installation of malware, theft of sensitive credentials stored in the browser profile, or use of the compromised system as part of a botnet.
This vulnerability aligns with Common Weakness Enumeration (CWE) category CWE-843, which refers to Accessing Memory Location using Wrong Type, and is closely related to CWE-120 Buffer Copy without Checking Size of Input if it involves memory corruption leading to overflow conditions. In the context of the MITRE ATT&CK framework, this exploit technique falls under Tactic Execution (TA0002) with specific techniques such as Command and Scripting Interpreter abuse or potentially Process Injection depending on how the arbitrary code execution is leveraged post-exploitation. The attack vector corresponds to Initial Access via Spearphishing Link if delivered through malicious websites, though it can also be triggered by drive-by downloads from compromised legitimate sites.
Mitigation strategies primarily involve applying the vendor-provided security updates that address the underlying memory management flaws in V8. Users and administrators should ensure that Google Chrome is updated to version 154.0.8037.57 or later immediately upon availability, as this patch resolves the type checking logic errors responsible for the confusion. Additionally, defense-in-depth measures such as enabling Site Isolation can help mitigate the impact by ensuring that cross-origin data remains isolated in separate processes, thereby limiting an attacker's ability to leverage memory corruption across different security contexts. Regularly updating browser components and disabling unnecessary plugins or extensions further reduces the attack surface available for exploitation of such engine-level vulnerabilities.