CVE-2020-6420 in Chrome
Summary
by MITRE
Insufficient policy enforcement in media in Google Chrome prior to 80.0.3987.132 allowed a remote attacker to bypass same origin policy via a crafted HTML page.
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Analysis
by VulDB Data Team • 05/10/2025
The vulnerability identified as CVE-2020-6420 represents a critical security flaw in Google Chrome's handling of media resources that undermines the fundamental same origin policy protection mechanism. This weakness existed in Chrome versions prior to 80.0.3987.132 and allowed remote attackers to execute unauthorized cross-origin operations through carefully crafted HTML content. The same origin policy serves as a cornerstone of web security by preventing scripts from one origin from accessing resources from another origin without proper authorization, making this bypass particularly dangerous for user privacy and data protection.
The technical implementation of this vulnerability stems from inadequate validation of media resource access controls within Chrome's rendering engine. When processing media elements such as videos, audio files, or images from different origins, the browser failed to properly enforce access restrictions that should prevent unauthorized data retrieval or manipulation. Attackers could craft malicious HTML pages that leveraged this flaw to access media resources that should have been restricted based on origin policies, effectively circumventing the browser's security boundaries.
The operational impact of CVE-2020-6420 extends beyond simple privilege escalation as it enables sophisticated cross-site attacks that could compromise user data confidentiality. Remote attackers could potentially extract sensitive information from media resources hosted on different domains, including embedded content, user-generated media, or third-party resources that should remain protected. This vulnerability particularly affects scenarios where users visit malicious websites containing crafted media elements that attempt to access resources from other origins, potentially leading to data leakage or further exploitation.
This vulnerability maps to CWE-284, which describes improper access control in software systems, and aligns with ATT&CK technique T1059.001 for command and scripting interpreter. The flaw represents a classic case of insufficient privilege checking in web browser components, where the media processing subsystem failed to properly validate access permissions before allowing resource operations. Organizations should prioritize immediate patching of affected Chrome versions to mitigate the risk of exploitation, while security teams should monitor for indicators of compromise related to malicious web content that might leverage this vulnerability. The remediation process requires updating to Chrome version 80.0.3987.132 or later, which implements proper policy enforcement for media resource access, ensuring that same origin restrictions are properly maintained during media processing operations.