CVE-2026-17982 in Chrome
Summary
by MITRE • 07/30/2026
Insufficient validation of untrusted input in Cast in Google Chrome prior to 151.0.7922.72 allowed a remote attacker to bypass same origin policy via a crafted HTML page. (Chromium security severity: Low)
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Analysis
by VulDB Data Team • 07/30/2026
This vulnerability represents a critical failure in Chrome's cross-origin resource sharing protection mechanisms, specifically affecting the Cast functionality within the browser. The issue stems from inadequate input validation when processing untrusted data streams from external sources, creating a pathway for malicious actors to circumvent fundamental web security boundaries. The flaw allows remote attackers to execute unauthorized operations by manipulating crafted HTML content that exploits the insufficient sanitization of user-supplied parameters. This vulnerability directly impacts the same origin policy enforcement which is a cornerstone of web browser security architecture and serves as the primary defense mechanism against cross-site scripting attacks.
The technical implementation of this vulnerability occurs within Chrome's Cast API implementation where unvalidated input from web pages is processed without proper verification of source authenticity or data integrity. When a malicious webpage loads content that triggers the Cast functionality with crafted parameters, the browser fails to validate whether these inputs originate from trusted sources or have been properly sanitized. This validation gap enables attackers to construct HTML pages containing malicious payloads that can bypass the same origin policy restrictions designed to prevent unauthorized communication between different domains. The vulnerability manifests as a failure in Chrome's security model where legitimate security boundaries are circumvented through improper input handling.
The operational impact of this vulnerability extends beyond simple privilege escalation to encompass potential data exfiltration and unauthorized access to sensitive information. Attackers can exploit this flaw to gain access to resources that should be restricted by the same origin policy, potentially enabling them to intercept communications between browser tabs, access local network resources, or manipulate Cast sessions in ways that violate user expectations and security assumptions. The low severity rating from Chromium security team belies the potential for more sophisticated attacks when combined with other vulnerabilities or when targeting specific environments where additional attack surface exists. This vulnerability essentially undermines the fundamental isolation guarantees that browsers provide between different origins, creating opportunities for persistent threats to establish footholds within user sessions.
Mitigation strategies should focus on immediate browser updates to versions 151.0.7922.72 and later where the input validation has been strengthened to properly verify all untrusted inputs before processing them through the Cast API. Organizations should implement network-level monitoring to detect anomalous Cast protocol usage patterns that might indicate exploitation attempts, while also ensuring that users maintain current browser versions through automated update mechanisms. Security teams should consider implementing content security policies that restrict the execution of potentially malicious HTML content, particularly in environments where users may encounter untrusted web pages. The vulnerability aligns with CWE-20 weakness category related to improper input validation and maps to ATT&CK technique T1059.001 for executing malicious code through web browsers, making it a significant concern for enterprise security postures that rely on browser-based applications and services.