CVE-2026-87500 in Chrome
Summary
by MITRE • 09/09/2026
Improper validation of array index in ANGLE in Google Chrome prior to 153.0.8010.36 allowed a remote attacker to potentially execute arbitrary code outside 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 an improper validation of array index within the ANGLE graphics library component of Google Chrome prior to version 153.0.8010.36 represents a critical boundary condition error that undermines the browser's sandboxing mechanisms. This flaw is fundamentally rooted in how memory addresses are calculated and accessed during rendering operations, specifically when processing graphical primitives or shader instructions handled by ANGLE. The absence of rigorous bounds checking allows an attacker to manipulate array indices such that they point to unauthorized regions of memory outside the intended allocation boundaries. This type of error aligns with CWE-125, Out-of-bounds Read, and potentially CWE-787, Out-of-bounds Write, depending on whether the exploit involves reading sensitive data or overwriting control structures to achieve code execution. The severity is classified as High by Chromium security standards due to the direct implication of sandbox escape, which is a primary defense mechanism in modern web browsers designed to isolate untrusted content from the host operating system and user files.
From an operational perspective, this vulnerability enables remote attackers to execute arbitrary code outside the browser's restricted environment through a crafted HTML page hosted on a malicious website or delivered via phishing campaigns. The attack vector relies on social engineering or drive-by download techniques where the victim visits a webpage containing specially constructed JavaScript that triggers specific rendering paths within ANGLE. By exploiting the index validation failure, the attacker can achieve arbitrary read and write access to memory regions typically protected by the browser's sandbox boundaries. This capability allows for the bypass of critical security controls such as Site Isolation and Cross-Origin Read Blocking (CORB), effectively granting the malicious script full control over the process context in which Chrome operates. The exploitation chain likely involves triggering a specific WebGL or Canvas operation that causes ANGLE to perform an out-of-bounds access, leading to memory corruption that can be leveraged for arbitrary code execution with the privileges of the browser process.
The impact of this vulnerability extends beyond simple data theft, as it facilitates full system compromise if combined with other local vulnerabilities or misconfigurations. An attacker who successfully exploits this flaw gains the ability to inject and execute native code on the victim's machine, potentially installing malware, establishing persistence, or pivoting to internal network resources. This aligns with MITRE ATT&CK technique T1059, Command and Scripting Interpreter, as well as T1203, Exploitation for Client Execution, which describes how attackers leverage software vulnerabilities in client applications to execute malicious payloads. The breach of the sandbox is particularly dangerous because it neutralizes one of the most effective layers of defense against web-based attacks, allowing subsequent stages of an intrusion campaign to proceed with elevated privileges and reduced detection likelihood by endpoint security solutions that rely on process isolation for threat containment.
Mitigation strategies primarily involve immediate software updates to ensure all instances of Google Chrome are upgraded to version 153.0.8010.36 or later, where the array index validation logic has been corrected to enforce strict bounds checking before memory access operations occur. For organizations unable to patch immediately due to compatibility concerns, network-level controls such as web filtering proxies can be configured to block traffic from known malicious domains that host exploit kits targeting this specific vulnerability. Additionally, enabling Chrome's sandbox features and ensuring that Site Isolation is active can help limit the blast radius of any successful exploitation attempt by restricting cross-origin data access. Developers integrating ANGLE into custom applications should also audit their code for similar array indexing patterns, implementing rigorous input validation and using safe memory management practices to prevent out-of-bounds accesses that could lead to similar security breaches in other contexts.