CVE-2026-79015 in Chrome
Summary
by MITRE • 08/26/2026
Improper input validation in ServiceWorker in Google Chrome prior to 152.0.7977.65 allowed a remote attacker to bypass system access restrictions via a crafted HTML page. (Chromium security severity: Low)
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Analysis
by VulDB Data Team • 08/26/2026
The vulnerability identified as an improper input validation flaw within the Service Worker component of Google Chrome prior to version 152.0.7977.65 represents a significant deviation from expected browser sandboxing behaviors. Service Workers are scripts that run in the background, separate from web pages, enabling features such as offline experiences, push notifications, and background syncs. These components operate within a restricted execution environment designed to isolate them from direct access to sensitive system resources or user data unless explicitly permitted by security policies. The core technical flaw lies in the failure of the browser engine to adequately sanitize or validate inputs passed during the registration or activation phases of Service Workers. This lack of rigorous validation allows crafted HTML pages, which may be hosted on malicious sites or delivered via drive-by download techniques, to exploit parsing inconsistencies within the JavaScript execution context associated with these workers.
From a technical perspective, this vulnerability falls under the category of CWE-20: Improper Input Validation. The attacker leverages specific edge cases in how Chrome processes service worker registration scripts to bypass system access restrictions. By crafting an HTML page that includes maliciously formatted script content or manipulated metadata, the adversary can trick the browser into granting elevated privileges to a potentially hostile Service Worker. This effectively breaks the isolation model that prevents web applications from accessing local file systems, network interfaces, or other protected APIs without user consent. The severity is classified as Low by Chromium security standards because while it allows for privilege escalation within the context of the compromised tab or worker scope, it typically requires social engineering to convince a user to visit the crafted page and does not provide direct remote code execution on the host operating system outside the browser sandbox.
The operational impact of this vulnerability centers around unauthorized access to restricted resources through web-based vectors. A successful exploitation allows a remote attacker to bypass security controls that are intended to limit what content loaded from untrusted origins can do. This could lead to scenarios where sensitive data stored in IndexedDB or Cache API is exfiltrated, or where the malicious Service Worker performs actions on behalf of the user without proper authorization checks. While the immediate risk might be limited compared to critical severity flaws like arbitrary code execution, it undermines trust in web application security models and can facilitate further attacks such as session hijacking or cross-site scripting amplification if combined with other vulnerabilities. The ATT&CK framework categorizes this type of behavior under T1059: Command and Scripting Interpreter, specifically within the context of browser-based exploitation techniques that abuse legitimate system functions for malicious purposes.
Mitigation strategies primarily involve updating to a patched version of Google Chrome where these input validation checks have been hardened. For organizations managing large fleets of devices, ensuring timely deployment of security patches is critical to closing this attack surface. Additionally, administrators should enforce strict Content Security Policy (CSP) directives that limit the sources from which Service Workers can be registered and executed. Implementing CSP headers with restrictive script-src policies helps prevent the loading of unauthorized scripts that could attempt to exploit such validation flaws. Users are also advised to exercise caution when visiting unfamiliar websites or clicking on links in unsolicited communications, as social engineering remains a primary vector for delivering crafted HTML pages designed to trigger this vulnerability. Regular security audits and penetration testing focused on web application interactions with browser APIs can further identify similar weaknesses before they are exploited in the wild.