CVE-2026-95287 in Chrome
Summary
by MITRE • 09/29/2026
Missing authorization in Navigation in Google Chrome prior to 154.0.8037.57 allowed a remote attacker who had compromised the renderer process to bypass site isolation via a crafted HTML page. (Chromium security severity: Medium)
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Analysis
by VulDB Data Team • 09/29/2026
The vulnerability identified as missing authorization in navigation within Google Chrome versions prior to 154.0.8037.57 represents a critical failure in the browser's access control mechanisms, specifically concerning how navigational requests are validated against current context permissions. This flaw allows an attacker who has already achieved code execution or arbitrary script injection within a renderer process to escalate their privileges by bypassing site isolation protections. Site isolation is a fundamental security architecture employed by modern browsers like Chrome and Chromium-based engines to prevent cross-site data theft, such as session hijacking or credential harvesting, by ensuring that sensitive resources are only accessible to the origin that owns them. When this mechanism fails due to improper authorization checks during navigation events, it effectively dismantles the boundary between different origins, allowing malicious content from one site to access private data belonging to another.
From a technical perspective, the core issue lies in the handling of navigation requests initiated by compromised renderer processes. In normal operation, when a user or script attempts to navigate to a new URL, the browser's security model verifies that the initiating context has the necessary permissions and is not violating cross-origin restrictions. However, in this specific vulnerability scenario, the authorization check was either skipped or incorrectly evaluated for certain types of navigational triggers crafted via HTML pages. This oversight enables an attacker to force the browser to load resources from a target origin without proper validation, effectively tricking the renderer into treating content from a different site as if it were part of the current trusted context. The severity is classified as medium by Chromium security standards because while it requires initial compromise of the renderer process, the resulting loss of isolation significantly amplifies the potential impact on user privacy and data integrity.
The operational impact of this vulnerability is severe for users relying on Chrome or its derivatives to browse sensitive websites such as online banking portals, email services, or corporate intranets. An attacker leveraging this flaw could potentially read cookies, local storage contents, or other persistent state information associated with a victim's active sessions across different domains. This capability undermines the core promise of same-origin policy and site isolation, which are designed to contain breaches within individual tabs or windows. By bypassing these safeguards, an adversary can perform sophisticated cross-site scripting attacks that persist beyond simple DOM manipulation, potentially leading to full account takeover if session tokens are exfiltrated. The risk is particularly acute in environments where users frequently switch between high-value and low-trust websites, as the attacker could use a compromised page on a less secure site to target data from a more critical domain open in another tab or window.
Mitigation strategies primarily involve updating the browser software to version 154.0.8037.57 or later, where these authorization checks have been hardened and properly enforced during navigation events. For organizations deploying Chrome across enterprise environments, it is crucial to ensure that automatic updates are enabled so that users receive patches promptly after release. Additionally, administrators should consider implementing strict content security policies (CSP) within web applications hosted on their domains to limit the types of scripts and resources that can be executed, thereby reducing the attack surface even if a renderer process were somehow compromised. Monitoring for unusual navigation patterns or unexpected cross-origin requests in browser logs may also help detect exploitation attempts in real-time.
This vulnerability aligns with Common Weakness Enumeration (CWE) category CWE-269, which describes Improper Authorization, as it involves a failure to enforce proper access controls during a state-changing operation like page navigation. Furthermore, from the perspective of the MITRE ATT&CK framework, this flaw facilitates techniques associated with Initial Access and Persistence through browser exploitation, specifically enabling lateral movement within user sessions by stealing credentials or session tokens. The ability to bypass site isolation is particularly dangerous as it neutralizes one of the most effective defenses against modern web-based attacks, making timely patching essential for maintaining a robust security posture in digital environments.