CVE-2026-87612 in Chrome
Summary
by MITRE • 09/09/2026
Type confusion in V8 in Google Chrome prior to 153.0.8010.36 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 • 09/09/2026
The vulnerability identified as a type confusion flaw within the V8 JavaScript engine, which powers Google Chrome prior to version 153.0.8010.36, represents a critical memory safety issue that undermines the integrity of the browser's execution environment. Type confusions occur when an application incorrectly assumes the data type of a variable or object in memory, leading to operations being performed on data structures with incompatible types. In the context of V8, this typically involves misinterpreting JavaScript objects as different internal representations, such as confusing a heap-allocated object with a primitive value or vice versa. This discrepancy allows an attacker who controls the input data to manipulate how the engine handles memory addresses and values, effectively bypassing the strict type checking mechanisms that are fundamental to preventing undefined behavior in high-level languages like JavaScript.
From a technical perspective, this flaw exploits the complex interaction between V8's Just-In-Time compiler and its garbage collector. When a crafted HTML page is loaded, it contains maliciously constructed JavaScript code designed to trigger specific edge cases within the engine's optimization pipelines or runtime type checks. By carefully crafting objects with particular shapes or hidden classes, an attacker can force V8 to cache incorrect type information. Subsequently, when this cached information is used during execution, the engine may perform memory reads or writes at arbitrary locations based on the misinterpreted type. This leads to out-of-bounds accesses or heap corruption, which are precursors to more severe exploitation techniques such as arbitrary read and write primitives.
The operational impact of this vulnerability is significant due to its potential for remote code execution within the browser's sandboxed environment. Although modern browsers employ multiple layers of defense including DEP, ASLR, and site isolation, a successful type confusion exploit can often bypass these protections by establishing precise control over memory layout. Once an attacker achieves arbitrary read/write capabilities inside the V8 heap, they can proceed to escape the renderer process sandbox. This escalation allows the execution of native code with higher privileges than those granted to standard web content, potentially leading to full system compromise if further exploitation steps are successful against other components like the browser's utility processes or host operating system defenses.
This vulnerability aligns closely with CWE-843, which describes access to incorrect type assumptions, and is frequently associated with CWE-120, buffer overflow overruns, as the immediate consequence of the type confusion often involves writing beyond allocated boundaries. In terms of offensive security frameworks, this exploit path maps to MITRE ATT&CK technique T1203, exploitation for client execution, where attackers leverage software vulnerabilities in applications on end-user systems. The high severity rating assigned by Chromium reflects the ease with which such memory corruption bugs can be chained into functional exploits that bypass modern browser mitigations.
Mitigation strategies primarily involve applying the vendor-provided security updates to upgrade Google Chrome and its underlying V8 engine to version 153.0.8010.36 or later, where these specific type confusion issues have been addressed through rigorous code audits and fuzzing efforts. For organizations unable to patch immediately, implementing strict content security policies can help mitigate the risk by restricting the execution of inline scripts and limiting sources from which JavaScript can be loaded. Additionally, enabling sandbox enforcement features such as site isolation ensures that even if a renderer process is compromised, the attacker cannot easily access sensitive data or escalate privileges across different origins. Continuous monitoring for anomalous network behavior originating from browser processes may also provide early detection indicators of exploitation attempts targeting this class of vulnerabilities.