CVE-2026-102330 in Chrome
Summary
by MITRE • 09/29/2026
Incorrect authorization in SiteIsolation in Google Chrome prior to 154.0.8037.92 allowed a remote attacker who had compromised the renderer process to bypass web origin policy via a crafted HTML page. (Chromium security severity: Low)
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Analysis
by VulDB Data Team • 09/29/2026
The vulnerability identified as an incorrect authorization flaw within Google Chrome's SiteIsolation mechanism prior to version 154.0.8037.92 represents a significant breach in the browser's process isolation architecture. SiteIsolation is a critical security feature designed to prevent cross-site scripting attacks and data theft by ensuring that content from different origins runs in separate processes. This architectural separation prevents malicious scripts loaded from one origin from accessing sensitive data, such as cookies or local storage, belonging to another origin running in a distinct process. The flaw arises when the authorization checks governing these inter-process boundaries are insufficiently rigorous, allowing a compromised renderer process to circumvent the expected restrictions imposed by web origin policies.
From a technical perspective, this vulnerability falls under the category of improper access control, specifically mapping to CWE-269: Improper Privilege Management or CWE-862: Missing Authorization depending on the specific implementation details of how the privilege escalation occurs within the renderer context. The core issue lies in the failure of the browser's security model to correctly validate whether a process has the necessary permissions to access resources associated with a different origin. When an attacker successfully compromises a renderer process, typically through a separate vulnerability such as a remote code execution flaw or a sophisticated cross-site scripting attack that achieves arbitrary script execution, they gain control over that specific sandboxed environment. Under normal circumstances, this compromise should be contained within the isolated process. However, due to the authorization error in SiteIsolation, the attacker can exploit the flawed logic to perform actions across origin boundaries, effectively breaking the isolation guarantee that Chrome relies upon for security.
The operational impact of this vulnerability is severe because it undermines one of the primary defenses against cross-site data theft and session hijacking. By bypassing web origin policies via a crafted HTML page or malicious script executed within the compromised renderer, an attacker can potentially access sensitive user information from other sites that are open in the same browser profile but run in different processes. This includes accessing cookies, local storage, IndexedDB entries, or other site-specific data belonging to high-value targets such as banking portals, email services, or corporate intranets. The ability to read this cross-origin data allows for session hijacking, where an attacker can steal authentication tokens and impersonate the user on their behalf without needing further credentials. This transforms a contained renderer compromise into a full account takeover scenario with significant financial and privacy implications for the end-user.
This behavior aligns closely with MITRE ATT&CK techniques related to browser security bypasses and data exfiltration from local systems. Specifically, it relates to T1059: Command and Scripting Interpreter if used in conjunction with other exploits, but more directly maps to T1213: Data from Information Repositories or T1530: Data from Local System when the attacker extracts sensitive files or data stored locally by the browser. The attack vector is classified as remote via a crafted HTML page, indicating that no user interaction beyond visiting a malicious site or being redirected to one is required if the renderer was already compromised through another means such as drive-by downloads or exploit kits targeting other vulnerabilities in plugins or JavaScript engines.
Mitigation for this vulnerability requires immediate action by updating Google Chrome to version 154.0.8037.92 or later, where these authorization checks have been corrected and the SiteIsolation boundaries are properly enforced. For organizations managing large fleets of devices, automated patch management systems should be configured to prioritize browser updates due to the high prevalence of this attack vector in the wild. Additionally, users can employ additional layers of defense such as strict Content Security Policy headers on their own websites to limit script execution capabilities and reduce the likelihood of initial renderer compromise. Enabling enhanced protection modes or sandboxing features within enterprise browsers can also help mitigate the impact if a vulnerability is exploited by restricting the scope of what any single process can access, thereby reducing the blast radius even in the presence of underlying browser flaws.