CVE-2026-87641 in Chrome
Summary
by MITRE • 09/09/2026
Race condition in Browser in Google Chrome prior to 153.0.8010.36 allowed a remote attacker to bypass system access restrictions via a crafted HTML page. (Chromium security severity: Medium)
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Analysis
by VulDB Data Team • 09/09/2026
The vulnerability identified as a race condition within the browser engine of Google Chrome versions prior to 153.0.8010.36 represents a critical flaw in how the application manages concurrent access to system resources and state variables. This type of defect typically arises when multiple threads or processes attempt to read and modify shared data simultaneously without adequate synchronization mechanisms, such as locks or atomic operations. In the context of web browsers, this often involves complex interactions between JavaScript execution contexts, rendering engines, and native browser components that handle permissions and security policies. The specific nature of a race condition allows an attacker to exploit timing windows where the application's state is inconsistent or transitional, effectively creating a gap in the logical flow of security checks.
A remote attacker can leverage this vulnerability by hosting or directing users to a specially crafted HTML page containing malicious JavaScript code designed to trigger concurrent operations that outpace the browser's ability to enforce access controls. By carefully timing these operations, the attacker can manipulate internal state variables before they are properly validated against current permission policies. This manipulation allows the script to bypass system access restrictions that would normally prevent unauthorized actions, such as accessing sensitive APIs, reading protected memory regions, or interacting with other tabs and windows in ways that violate same-origin policy constraints. The Chromium security team has classified this issue with a medium severity rating, indicating that while it requires user interaction via a crafted page, the potential for privilege escalation within the browser sandbox is significant enough to warrant immediate attention.
The operational impact of this vulnerability extends beyond simple data leakage or script execution errors. By bypassing system access restrictions, an attacker could potentially escalate privileges from untrusted web content to more privileged contexts within the browser process model. This might include accessing local file systems, interacting with hardware interfaces exposed through Web APIs, or compromising cross-origin isolation policies that are designed to isolate sensitive sites from less trusted ones. Such a breach undermines the fundamental security boundaries established by modern browsers, potentially leading to further exploitation vectors such as arbitrary code execution if combined with other vulnerabilities in native components. The ability to bypass these restrictions effectively neutralizes several layers of defense intended to protect user privacy and system integrity against malicious web content.
Mitigation strategies primarily involve updating the browser software to version 153.0.8010.36 or later, where Google has implemented fixes for the underlying synchronization issues in the race condition logic. Until such updates are applied, users should exercise heightened caution when visiting untrusted websites and consider using additional security tools that enforce stricter content policies. From a development perspective, addressing this flaw requires rigorous code review focused on concurrency control, ensuring that all shared resources accessed by multiple threads are protected with appropriate locking mechanisms or atomic operations. Furthermore, implementing robust state validation checks at critical points in the execution flow can help detect and prevent exploitation attempts even if timing windows exist. This incident aligns with CWE-362, which describes concurrent access to shared resources without proper synchronization, and relates to ATT&CK techniques involving browser-based attacks that exploit client-side software vulnerabilities for initial access or privilege escalation within a compromised environment.