CVE-2026-87631 in Chrome
Summary
by MITRE • 09/09/2026
Missing authorization in DOM in Google Chrome prior to 153.0.8010.36 allowed a remote attacker to potentially leak sensitive information via a crafted HTML page. (Chromium security severity: Low)
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Analysis
by VulDB Data Team • 09/09/2026
The vulnerability identified as missing authorization within the Document Object Model of Google Chrome represents a critical failure in access control mechanisms that govern how web content interacts with browser internals. This flaw, present in versions prior to 153.0.8010.36, stems from an insufficient validation process when handling DOM APIs or properties that should be restricted based on the origin context of the executing script. In a secure browsing environment, cross-origin isolation is paramount to prevent malicious scripts running on untrusted websites from accessing sensitive data belonging to other origins. The absence of proper authorization checks allows a remote attacker to bypass these boundaries by crafting specific HTML pages that exploit this gap in logic.
From a technical perspective, the Document Object Model serves as the interface through which web pages interact with browser features such as cookies, local storage, and navigation history. When an application fails to verify whether the calling context has the requisite permissions before exposing internal state or allowing manipulation of sensitive properties, it creates a pathway for information disclosure. An attacker can leverage this by embedding malicious code within a webpage that triggers these unprotected DOM functions. Because the browser does not adequately distinguish between legitimate user-initiated actions and automated script-driven requests in certain edge cases, the security boundary is effectively neutralized. This type of flaw aligns with CWE-269, which describes Improper Privilege Management, specifically where an actor obtains privileges or access to resources without proper authorization checks being enforced by the system.
The operational impact of this vulnerability centers on the potential leakage of sensitive information that should remain isolated within a specific browsing context. While classified as low severity in Chromium's internal security metrics due to the complexity required for exploitation and the limited scope of data typically accessible through DOM manipulation, it still poses a tangible risk. An attacker could potentially extract session identifiers, authentication tokens, or other user-specific data stored in browser-accessible locations if those resources are exposed via the vulnerable API endpoints. This compromises the confidentiality aspect of the security triad, allowing for potential follow-on attacks such as account takeover or targeted phishing campaigns that rely on accurate contextual information about the victim's browsing activity.
This incident maps directly to several techniques within the MITRE ATT&CK framework, particularly those related to Collection and Exfiltration over alternative protocols or through client-side scripting. The specific behavior of reading sensitive data from a web page context without proper origin checks corresponds to T1059.007, which covers JavaScript as an execution vector for malicious activities including data theft. Furthermore, the lack of strict enforcement regarding cross-origin resource sharing principles touches upon broader categories of browser security misconfigurations that attackers exploit to maintain persistence or gather intelligence on high-value targets without triggering standard intrusion detection systems.
Mitigation strategies primarily involve updating the Google Chrome installation to version 153.0.8010.36 or later, where these authorization checks have been rigorously implemented and tested by Chromium engineers. For organizations managing large fleets of endpoints, automated patch management solutions should be configured to prioritize this update due to its nature as a remote code execution vector that does not require user interaction beyond visiting the crafted webpage. Additionally, implementing Content Security Policy headers can provide an additional layer of defense by restricting the sources from which scripts are allowed to execute and limiting their ability to access sensitive DOM properties even if such vulnerabilities exist in future releases. Regular security audits focusing on cross-origin isolation policies and strict origin validation for all browser APIs will further reduce the attack surface associated with client-side scripting environments.