CVE-2026-121210 in Chrome
Summary
by MITRE • 11/03/2026
Type confusion in V8 in Google Chrome prior to 157.0.8103.38 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 • 11/03/2026
The vulnerability identified as a type confusion flaw within the V8 JavaScript engine, which powers Google Chrome prior to version 157.0.8103.38, represents a critical failure in memory safety and runtime integrity checks. Type confusion vulnerabilities occur when an application incorrectly handles data types during execution, leading to scenarios where one part of the program treats a value as having one type while another part interprets it differently. In the context of V8, this typically involves JavaScript objects being misinterpreted by the underlying C++ code or JIT compiler optimizations. An attacker could exploit this discrepancy by crafting a specific HTML page containing malicious JavaScript that triggers the erroneous type interpretation. This exploitation path allows for arbitrary memory reads and writes, which is particularly dangerous because it bypasses standard security boundaries within the browser environment.
The operational impact of this vulnerability is severe due to its potential for remote code execution inside the sandboxed renderer process. Modern browsers utilize a multi-process architecture where each tab or frame runs in a restricted sandbox to limit the damage caused by successful exploits. However, type confusion bugs often provide the necessary primitives to escape these sandboxes through techniques such as arbitrary read/write operations and control flow hijacking. By manipulating object shapes and hidden classes within V8, an attacker can achieve precise memory layout manipulation, leading to code execution with the privileges of the browser process or potentially escalating to system-level access depending on the specific exploitation chain employed. The Chromium security team classified this issue as High severity, reflecting its significant potential for widespread compromise across user systems relying on affected Chrome versions.
From a classification perspective, this vulnerability aligns closely with CWE-843, which denotes Access of Incorrect Type or Misinterpretation of Provided Data. This category encompasses errors where the program fails to properly validate or cast data types before use, leading to undefined behavior that can be leveraged for malicious purposes. Furthermore, in terms of offensive security frameworks like MITRE ATT&CK, this vulnerability facilitates initial access and privilege escalation techniques often associated with T1203 Exploitation for Client Execution and potentially T1059 Command and Scripting Interpreter if the attacker utilizes JavaScript as a vehicle for further payload delivery. The ability to execute arbitrary code via a crafted web page also touches upon lateral movement vectors within enterprise environments where browser-based attacks are common entry points.
Mitigation strategies primarily involve immediate patching of the V8 engine by updating Google Chrome to version 157.0.8103.38 or later, which includes fixes for these type confusion issues. Security teams should ensure that automatic update mechanisms are enabled across all endpoints to minimize exposure windows. Additionally, deploying browser hardening techniques such as disabling JavaScript in untrusted sites or using extensions that restrict script execution can provide an additional layer of defense against exploitation attempts. Continuous monitoring for anomalous network traffic originating from internal hosts may also help detect post-exploitation activities resulting from successful compromises before they escalate into broader incidents.