CVE-2026-87646 in Chrome
Summary
by MITRE • 09/09/2026
Use after free in Web Authentication in Google Chrome prior to 153.0.8010.36 allowed a remote attacker to 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 a use-after-free error within the Web Authentication component of Google Chrome prior to version 153.0.8010.36 represents a critical memory management flaw that compromises the integrity and confidentiality of user data. This specific class of vulnerabilities, categorized under CWE-416 in the Common Weakness Enumeration standard, occurs when a program continues to use a pointer after it has been freed from memory. In the context of browser security, such errors are particularly dangerous because they can lead to arbitrary code execution if an attacker can control the data written into the reclaimed memory space before it is reallocated for another purpose. The Web Authentication API, which facilitates secure login processes using hardware tokens or biometrics, involves complex interactions between JavaScript and native C++ components within the browser engine. A flaw in this interface allows a remote attacker to manipulate these internal structures through maliciously crafted web content.
The operational impact of this vulnerability is severe due to its potential for sandbox escape. Modern browsers rely on a multi-process architecture where each tab or site runs in an isolated environment known as a sandbox, designed to prevent compromised pages from accessing sensitive system resources or other tabs. However, when a use-after-free condition exists within the Web Authentication module, it can be exploited by a remote attacker via a specially crafted HTML page hosted on a malicious website. By triggering the vulnerability during the authentication handshake process, an attacker may gain control over memory pointers and subsequently execute arbitrary code with higher privileges than those granted to the browser sandbox. This effectively breaks down the isolation boundaries that protect users from drive-by download attacks or session hijacking attempts originating from untrusted web sources.
From a threat intelligence perspective, this vulnerability aligns with techniques described in the MITRE ATT&CK framework, specifically relating to initial access and privilege escalation vectors used by advanced persistent threats. Attackers often leverage such browser vulnerabilities as part of their toolkit for delivering malware or stealing credentials without requiring user interaction beyond visiting a compromised page. The high severity rating assigned by Chromium security teams reflects the ease with which this flaw can be weaponized in real-world phishing campaigns or malicious ad networks where users are tricked into loading specific scripts that exploit the memory corruption bug.
Mitigation strategies primarily involve updating to Google Chrome version 153.0.8010.36 or later, which contains patches addressing the memory management logic within the Web Authentication component. Organizations should enforce automatic update policies for all endpoints running this browser to ensure timely protection against known exploits. Additionally, security teams can implement content security policies and sandboxing configurations that restrict the execution of untrusted scripts, although these measures serve as secondary defenses since the root cause lies in the application code itself rather than configuration errors. Regular vulnerability scanning and monitoring for indicators of compromise related to memory corruption attacks are also recommended to detect potential exploitation attempts before they result in full system compromise.