CVE-2026-106240 in Chrome
Summary
by MITRE • 10/06/2026
Type confusion in V8 in Google Chrome prior to 155.0.8059.39 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 • 10/07/2026
The vulnerability identified as a type confusion flaw within the V8 JavaScript engine, which powers Google Chrome prior to version 155.0.8059.39, represents a critical memory safety issue that allows for arbitrary code execution in a highly restricted environment. Type confusion vulnerabilities occur when an application incorrectly assumes the data type of a variable or object during runtime operations. In the context of V8, this typically involves the engine misinterpreting the internal structure or representation of a JavaScript object due to flawed logic in its Just-In-Time compilation process or garbage collection mechanisms. When such a flaw is triggered by a crafted HTML page served from a remote server, it enables an attacker to manipulate memory layouts in ways that bypass standard security boundaries. The severity of this issue is classified as High because it directly impacts the core execution engine responsible for running web content, making it a prime target for exploitation campaigns aiming at end-users browsing malicious websites or clicking on compromised links.
From a technical perspective, type confusion flaws often arise when V8 fails to properly validate object types before performing operations that depend on specific memory layouts. For instance, if the engine treats an integer as a pointer or vice versa due to incorrect assumptions about variable states, it can lead to out-of-bounds reads or writes. This misalignment allows attackers to craft payloads that exploit these discrepancies to achieve arbitrary read and write primitives within the browser process. The ability to perform arbitrary memory operations is particularly dangerous because it serves as the foundational step for more complex exploitation techniques. By carefully manipulating heap structures through JavaScript code embedded in a malicious webpage, an attacker can construct gadgets or overwrite function pointers, ultimately gaining control over the instruction pointer of the V8 engine.
The operational impact of this vulnerability extends beyond simple data leakage due to its potential for arbitrary code execution within the browser sandbox. Although modern browsers employ multiple layers of defense such as Site Isolation, Control Flow Integrity, and hardware-enforced stack protection, a successful type confusion exploit can still lead to sandbox escape under certain conditions or result in severe compromise if these mitigations are bypassed. An attacker leveraging this flaw could execute arbitrary commands on the victim's system, install malware, steal sensitive credentials stored within the browser session, or pivot further into internal networks depending on the user's privileges and network configuration. The fact that the exploit is triggered via a standard HTML page means it requires no additional plugins or external software installations, significantly lowering the barrier to entry for attackers and increasing the likelihood of successful exploitation in drive-by download scenarios.
This vulnerability aligns with Common Weakness Enumeration (CWE) category CWE-843, which refers to Accessing Memory Location using Wrong Pointer Type, a subset of broader memory safety issues like CWE-119 Improper Restriction of Operations within the Bounds of a Memory Buffer. In terms of attack behavior, it maps closely to MITRE ATT&CK technique T1059 Command and Scripting Interpreter, specifically through JavaScript execution, followed by potential lateral movement or privilege escalation techniques if sandbox escape is achieved. The exploitation vector falls under Remote Code Execution via Web Content, highlighting the risk associated with rendering untrusted HTML content without sufficient type validation at the engine level.
Mitigation for this vulnerability primarily involves updating Google Chrome to version 155.0.8059.39 or later, where the underlying logic errors in V8 have been corrected by the Chromium security team. Organizations should ensure that automatic updates are enabled to minimize the window of exposure. For users unable to update immediately, employing browser hardening techniques such as disabling JavaScript for untrusted sites using extensions like NoScript can provide a layer of defense against type confusion exploits triggered via web pages. Additionally, keeping operating systems and other software components up to date ensures that secondary mitigation layers like ASLR and DEP remain effective in limiting the impact if an exploit attempt occurs. Regular security audits and penetration testing focused on browser-based attack vectors are also recommended to identify similar weaknesses before they can be exploited by malicious actors targeting high-value environments.