CVE-2026-17700 in Chrome
Summary
by MITRE • 07/30/2026
Insufficient validation of untrusted input in Actor in Google Chrome prior to 151.0.7922.72 allowed a remote attacker who had compromised the renderer process to leak cross-origin data 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 handling of untrusted input within its actor subsystem, specifically affecting versions prior to 151.0.7922.72. The issue stems from inadequate validation mechanisms that fail to properly sanitize or verify data originating from untrusted sources, creating a pathway for cross-origin information leakage. The vulnerability is classified as High severity by Chromium security standards and exploits a specific weakness in the renderer process execution environment where attackers can manipulate input handling to extract sensitive data across origin boundaries.
The technical implementation of this flaw occurs when an attacker successfully compromises the renderer process through previously exploited vulnerabilities or social engineering tactics. Once inside the renderer context, the malicious actor can craft specially designed HTML pages that leverage the insufficient input validation to traverse security boundaries established by the browser's same-origin policy. This allows for unauthorized data access and potential information disclosure between different origins, effectively bypassing fundamental web security mechanisms that protect user privacy and application integrity.
Operational impact of this vulnerability extends beyond simple data leakage, as it provides attackers with a method to gather sensitive information from other domains or applications running within the same browser instance. The cross-origin nature of the attack means that malicious actors can potentially access cookies, local storage, session data, and other origin-specific resources that should remain isolated. This capability significantly increases the risk profile for users, as it can be combined with other exploits to create more sophisticated attacks targeting specific applications or user accounts.
The vulnerability aligns with CWE-20, which describes "Improper Input Validation" as a fundamental weakness in software design that allows malicious inputs to bypass security checks. From an ATT&CK framework perspective, this represents a technique for privilege escalation and information gathering through process compromise and data exfiltration. The attack vector specifically maps to T1059.007 for browser script execution and T1566 for credential access through compromised applications.
Mitigation strategies should prioritize immediate patching of affected Chrome versions to 151.0.7922.72 or later, which includes the necessary input validation improvements. Organizations should implement network monitoring to detect suspicious HTML content delivery patterns and consider browser hardening configurations that restrict cross-origin resource access. Additionally, regular security assessments should verify that renderer process isolation remains intact and that no additional vulnerabilities exist in the browser's actor subsystem that could compound this weakness. Users should be educated about the risks of visiting untrusted websites and the importance of keeping browser software updated to prevent exploitation of such critical flaws.