CVE-2026-17882 in Chrome
Summary
by MITRE • 07/30/2026
Policy bypass in Extensions in Google Chrome prior to 151.0.7922.72 allowed an attacker who convinced a user to install a malicious extension to bypass site isolation via a crafted Chrome Extension. (Chromium security severity: Medium)
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Analysis
by VulDB Data Team • 07/30/2026
This vulnerability represents a critical policy bypass in Google Chrome's extension architecture that could enable attackers to circumvent essential security boundaries through malicious extensions. The flaw existed in Chrome versions prior to 151.0.7922.72 and specifically targeted the site isolation mechanisms that are fundamental to Chrome's security model. Site isolation is a core defense-in-depth strategy designed to prevent malicious websites from accessing data from other sites by running each site in a separate process, thereby creating process-level boundaries that protect user privacy and system integrity.
The technical nature of this vulnerability stems from insufficient validation of extension permissions and policies within the browser's extension management system. When users installed malicious extensions, the vulnerable Chrome versions failed to properly enforce security restrictions that should have prevented these extensions from accessing or manipulating site isolation boundaries. This policy bypass allowed attackers to craft extensions that could directly interact with processes belonging to other sites, effectively breaking the isolation that Chrome normally maintains between different web origins.
The operational impact of this vulnerability extends beyond simple privilege escalation as it represents a fundamental failure in Chrome's security architecture. Attackers who successfully convinced users to install malicious extensions could potentially access sensitive data from other websites, perform cross-site scripting attacks, or manipulate browser processes in ways that violate the principle of least privilege. The medium severity rating reflects the requirement for user interaction through extension installation, but also acknowledges that once a user installs an extension, the attacker gains significant control over the browser's security boundaries. This vulnerability directly impacts the chromium security model and could enable sophisticated attacks such as credential theft or data exfiltration from other browsing sessions.
Mitigation strategies for this vulnerability focus on immediate remediation through Chrome updates to version 151.0.7922.72 or later, which contain the necessary patches to address the policy bypass mechanism. Organizations should also implement strict extension management policies that limit extension installation privileges and conduct regular audits of installed extensions. The fix likely involves strengthening validation checks within Chrome's extension permission system and ensuring that extension installations properly enforce security boundaries that maintain site isolation. From an att&ck perspective, this vulnerability maps to techniques involving privilege escalation and persistence through browser extensions, while the cwe classification would likely fall under cwe-284 access control violations or cwe-352 cross-site request forgery related to improper enforcement of security boundaries.