CVE-2026-87577 in Chrome
Summary
by MITRE • 09/09/2026
Incorrect authorization in Isolated in Google Chrome prior to 153.0.8010.36 allowed a remote attacker to bypass web origin policy into a privileged page 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 an incorrect authorization flaw within the Isolated World feature of Google Chrome prior to version 153.0.8010.36 represents a significant breach in web origin policy enforcement. This issue stems from a logic error where the browser fails to properly validate access controls for scripts executing within isolated contexts, which are designed to provide sandboxed environments with restricted permissions compared to standard pages. By exploiting this misconfiguration, a remote attacker can craft a malicious HTML page that tricks the browser into granting elevated privileges or unauthorized access to sensitive data and functionality intended only for privileged origins. This bypass effectively undermines the fundamental security model of web browsers, which relies on strict separation between different sources of content to prevent cross-site attacks.
From a technical perspective, this flaw aligns with CWE-269, Improper Privilege Management, as it involves an actor obtaining privileges or accessing resources without proper authorization checks. The attack vector is classified under ATT&CK technique T1059, Command and Scripting Interpreter, specifically through the use of HTML-based scripts to execute unauthorized actions within the browser environment. When a user visits a maliciously crafted webpage, the attacker leverages the flawed isolation mechanism to inject code that interacts with privileged pages or APIs that should remain inaccessible from untrusted origins. This allows for potential data exfiltration, session hijacking, or further exploitation of other vulnerabilities by establishing a foothold within a higher-privilege context than intended by the browser's security architecture.
The operational impact of this vulnerability is substantial, as it compromises the integrity and confidentiality of user data protected by origin policies. Attackers can potentially access sensitive information such as cookies, local storage contents, or DOM elements from other tabs or windows that share the same isolated world but were meant to be segregated based on security boundaries. This could lead to account takeover if session tokens are accessible, or privacy violations through unauthorized tracking and data collection. Furthermore, because this is a remote code execution vector via HTML, it can be delivered through phishing campaigns or compromised websites without requiring any user interaction beyond visiting the page, increasing the likelihood of successful exploitation in real-world scenarios.
Mitigation for this vulnerability requires immediate updating to Google Chrome version 153.0.8010.36 or later, where these authorization checks have been corrected and strengthened. Organizations should enforce automated update policies across all endpoints running affected browser versions to ensure that the latest security patches are applied promptly. Additionally, users can employ content security policy headers on their own web applications to add an additional layer of defense against script injection attacks, although this does not directly fix the browser-side flaw. Security teams should also monitor for indicators of compromise related to unusual network traffic or unexpected access patterns from isolated contexts within internal systems that rely heavily on Chrome-based browsers for secure operations.