CVE-2026-17686 in Chrome
Summary
by MITRE • 07/30/2026
Insufficient validation of untrusted input in Passwords in Google Chrome prior to 151.0.7922.72 allowed a remote attacker who had compromised the renderer process to bypass site isolation via a crafted HTML page. (Chromium security severity: High)
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Analysis
by VulDB Data Team • 07/30/2026
This vulnerability represents a critical security flaw in Google Chrome's input validation mechanisms that could enable remote attackers to circumvent site isolation protections when they have already compromised the renderer process. The issue stems from insufficient validation of untrusted input within password handling components, creating a pathway for privilege escalation attacks. The vulnerability affects Chrome versions prior to 151.0.7922.72 and demonstrates a significant weakness in the browser's security architecture.
The technical flaw manifests when a malicious actor with access to the renderer process crafts a specially designed HTML page that exploits weaknesses in how Chrome validates password-related input data. This allows the attacker to bypass the site isolation mechanisms that are fundamental to Chrome's security model, which are designed to prevent malicious websites from accessing data from other origins. The vulnerability operates at the boundary between trusted and untrusted input processing, where inadequate sanitization permits malicious code execution that could access cross-origin resources.
The operational impact of this vulnerability is severe as it undermines one of Chrome's core security features - site isolation - which protects users from cross-site scripting attacks and data leakage between different origins. An attacker who has already compromised the renderer process can leverage this flaw to expand their attack surface significantly, potentially accessing sensitive information from other websites or tabs. This creates a dangerous escalation path where initial compromise can lead to broader information disclosure and potential system access.
The vulnerability aligns with CWE-20, which addresses "Improper Input Validation," and relates to ATT&CK technique T1059.007 for command and scripting interpreter, as well as T1566 for malicious file execution through web-based attacks. Organizations should immediately update to Chrome version 151.0.7922.72 or later to mitigate this risk. Additional mitigations include implementing strict content security policies, enabling sandboxing features, and monitoring for unusual renderer process behavior that might indicate exploitation attempts. Security teams should also consider network-level protections such as web application firewalls and browser hardening measures to reduce the attack surface and prevent successful exploitation of similar input validation flaws.
The incident highlights the importance of comprehensive input validation across all browser components, particularly those handling sensitive user data like passwords. It demonstrates how seemingly minor validation gaps can enable significant security breaches when combined with other compromise vectors. Organizations should conduct regular security assessments focusing on input handling mechanisms and ensure that all browser components maintain strict validation protocols to prevent similar vulnerabilities from being exploited in the future.