CVE-2026-87598 in Chrome
Summary
by MITRE • 09/09/2026
Incorrect authorization in ServiceWorker in Google Chrome prior to 153.0.8010.36 allowed a remote attacker to bypass web origin policy 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 an incorrect authorization flaw within the Service Worker component of Google Chrome, specifically affecting versions prior to 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 whether a service worker has the appropriate permissions to access or manipulate resources associated with a specific origin. Service workers are scripts that run independently of web pages, enabling features such as offline experiences and push notifications, but they operate within strict security boundaries defined by the same-origin policy. When this authorization check is bypassed, it allows malicious actors to exploit these elevated privileges in contexts where they should not exist, effectively undermining the isolation mechanisms designed to protect user data and application integrity.
From a technical perspective, the core of this vulnerability lies in the mismanagement of context validation during service worker registration or execution phases. A remote attacker can craft an HTML page that triggers specific conditions within the browser's rendering engine, causing it to grant unauthorized access to sensitive APIs or resources belonging to other origins. This bypass allows the malicious script to read data, modify state, or perform actions on behalf of a victim user without proper consent or authentication checks. The severity is classified as low by Chromium security standards because while the mechanism for exploitation exists, successful attacks may require specific environmental conditions or additional social engineering components to achieve meaningful impact beyond theoretical access violations.
The operational impact of this vulnerability centers on the potential compromise of web application integrity and user privacy. By bypassing origin policies, an attacker could potentially exfiltrate sensitive information stored in local storage or session cookies associated with a target domain if those resources are accessible through the compromised service worker context. This can lead to unauthorized data access, cross-site scripting amplification scenarios where malicious payloads gain broader reach than intended, and potential manipulation of application behavior that relies on accurate origin verification for security decisions. Although the low severity rating suggests limited immediate exploitability in most standard configurations, it still poses a risk to environments with high-value targets or complex web applications that depend heavily on service worker capabilities for functionality such as caching strategies and background synchronization.
Mitigation efforts primarily involve updating Google Chrome to version 153.0.8010.36 or later, where the authorization logic has been corrected to ensure strict adherence to origin boundaries. Users should enable automatic updates to receive these patches promptly. For developers integrating service workers into their applications, it is crucial to implement robust security headers and validate all interactions with service worker APIs against expected origins explicitly in code rather than relying solely on browser enforcement during development phases. Additionally, monitoring for unusual network activity or unexpected behavior from background scripts can help detect potential exploitation attempts before significant damage occurs.
This vulnerability aligns with CWE-269, which describes Improper Authorization, as the root cause is a failure to enforce proper access controls over resources based on user identity and context. In terms of offensive security frameworks, it relates to ATT&CK technique T1059, Command and Scripting Interpreter, specifically when used in conjunction with browser-based execution environments like JavaScript within service workers. The exploitation vector falls under Remote Code Execution principles where the attacker leverages a web application interface to execute unauthorized actions. Understanding these classifications helps security teams prioritize patch management and configure detection rules that look for anomalies in service worker registration patterns or unexpected cross-origin resource requests initiated by background scripts, thereby enhancing overall defense-in-depth strategies against similar browser-based vulnerabilities.