CVE-2025-6556 in Chrome
Summary
by MITRE • 06/24/2025
Insufficient policy enforcement in Loader in Google Chrome prior to 138.0.7204.49 allowed a remote attacker to bypass content security policy via a crafted HTML page. (Chromium security severity: Low)
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Analysis
by VulDB Data Team • 06/26/2025
The vulnerability identified as CVE-2025-6556 represents a significant weakness in Google Chrome's content security policy enforcement mechanism within the loader component. This issue affects versions prior to 138.0.7204.49 and allows remote attackers to circumvent critical security protections through carefully crafted HTML pages. The flaw resides in the loader's insufficient policy enforcement capabilities, which should normally prevent unauthorized content execution and restrict potentially dangerous operations. The vulnerability operates at a fundamental level of web browser security architecture where policy enforcement mechanisms are designed to protect users from malicious content and unauthorized access patterns.
The technical implementation of this vulnerability stems from inadequate validation and enforcement of content security policies within Chrome's loading and processing pipeline. When a user encounters a maliciously crafted HTML page, the loader component fails to properly enforce the expected security boundaries that should prevent unauthorized script execution, resource loading, or cross-origin operations. This weakness creates an attack surface where remote adversaries can craft specific HTML content that bypasses the browser's normal security controls. The flaw demonstrates a failure in the principle of least privilege enforcement, where the loader component does not adequately validate or restrict the execution context of loaded content according to established security policies.
From an operational impact perspective, this vulnerability enables attackers to execute arbitrary code or access sensitive resources that should normally be restricted by content security policies. The low severity classification does not diminish the potential for exploitation, as attackers can leverage this weakness to perform various malicious activities including data exfiltration, cross-site scripting attacks, or privilege escalation within the browser environment. The remote nature of the attack means that victims can be compromised simply by visiting a malicious webpage, making this vulnerability particularly dangerous in phishing campaigns or compromised website scenarios. This weakness undermines the core security model of modern web browsers and could potentially be combined with other vulnerabilities to create more sophisticated attack vectors.
Security mitigations for this vulnerability primarily involve updating to Chrome version 138.0.7204.49 or later, which contains the necessary patches to properly enforce content security policies within the loader component. Organizations should implement comprehensive browser update management processes to ensure all systems receive the latest security patches promptly. Additional protective measures include implementing web application firewalls, monitoring for suspicious content delivery patterns, and maintaining strict content security policy configurations. The vulnerability aligns with CWE-693, which addresses protection mechanism failures, and could potentially map to ATT&CK technique T1059.001 for command and scripting interpreter execution. Network administrators should also consider implementing browser hardening configurations and regular security assessments to identify similar policy enforcement weaknesses that could compromise user security.