CVE-2026-79136 in Chrome
Summary
by MITRE • 08/26/2026
Incorrect authorization in ServiceWorker in Google Chrome prior to 152.0.7977.65 allowed a remote attacker to bypass web origin policy via a crafted HTML page. (Chromium security severity: Medium)
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Analysis
by VulDB Data Team • 08/26/2026
The vulnerability identified as an incorrect authorization flaw within the Service Worker implementation of Google Chrome, specifically affecting versions prior to 152.0.7977.65, represents a significant breach in web origin policy enforcement. This issue stems from a logical error or insufficient validation mechanism within the browser's handling of service worker registrations and their associated scopes. When a website registers a service worker, it defines a scope that determines which URLs are controlled by that worker. The security flaw allows an attacker to manipulate this registration process through a crafted HTML page, effectively tricking the browser into granting broader access permissions than intended for the originating context. This bypass of origin policies undermines one of the fundamental pillars of web security, which is designed to isolate content from different origins to prevent malicious scripts on one site from accessing data or performing actions on behalf of users on another trusted site.
From a technical perspective, this vulnerability falls under the category of improper access control, specifically aligning with CWE-284: Improper Access Control. The core issue lies in the failure of the browser's security model to correctly validate whether the requesting context has sufficient privileges to interact with or register service workers that might intercept network requests from other origins. By crafting a specific HTML page containing malicious JavaScript, an attacker can exploit this misconfiguration to execute code within the scope of a different origin. This capability allows for potential cross-origin data theft, session hijacking, or unauthorized actions performed on behalf of the user against third-party services they are authenticated with. The severity is classified as medium by Chromium security standards because while it requires user interaction and specific conditions to exploit, its impact can be severe depending on the sensitivity of the targeted applications.
The operational impact of this vulnerability extends beyond simple data leakage. It enables sophisticated phishing attacks where an attacker could potentially intercept or modify network requests made by legitimate web applications if those applications rely heavily on service workers for caching or background synchronization. An adversary leveraging this flaw could inject malicious payloads into cached responses, leading to drive-by downloads or the execution of arbitrary code within a trusted context. This compromises the integrity and confidentiality guarantees provided by the Same-Origin Policy (SOP). Users visiting compromised pages may unknowingly expose sensitive information such as authentication tokens, personal data, or financial details stored in local storage or accessed via XMLHttpRequests that are intercepted due to the flawed authorization logic.
Mitigation strategies primarily involve updating the browser software to version 152.0.7977.65 or later, where these access control checks have been hardened and validated against such bypass techniques. For organizations managing enterprise deployments of Chrome, it is critical to ensure that automatic updates are enabled or manually push this patch across all endpoints to minimize the window of exposure. Additionally, developers should adhere to strict Content Security Policy (CSP) configurations to restrict the sources from which scripts can be loaded and executed, thereby reducing the attack surface even if a browser vulnerability exists. Monitoring for unusual service worker registrations in web application logs can also serve as an early detection mechanism for exploitation attempts.
In terms of threat intelligence frameworks, this type of exploit aligns with MITRE ATT&CK technique T1059: Command and Scripting Interpreter, specifically when used to facilitate further malicious activities after gaining a foothold through the origin bypass. It also relates to T1534: Internal Spearphishing if leveraged in targeted campaigns where users are tricked into visiting crafted pages that exploit this browser flaw. Security teams should prioritize patch management cycles and employ web application firewalls with rulesets capable of detecting anomalous service worker registration patterns or unusual cross-origin request behaviors associated with such exploitation attempts.