CVE-2020-6413 in Chrome
Summary
by MITRE
Inappropriate implementation in Blink in Google Chrome prior to 80.0.3987.87 allowed a remote attacker to bypass HTML validators via a crafted HTML page.
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Analysis
by VulDB Data Team • 05/10/2025
The vulnerability identified as CVE-2020-6413 represents a critical implementation flaw within the Blink rendering engine that powers Google Chrome and related browsers. This issue stems from an inadequate validation mechanism that fails to properly enforce HTML standards during page rendering processes. The flaw specifically manifests when the browser encounters crafted HTML content that exploits gaps in the validation logic, allowing malicious actors to circumvent expected security boundaries. Such vulnerabilities are particularly dangerous as they can be leveraged to execute unauthorized operations or bypass security controls that should normally prevent malicious activities.
The technical implementation flaw resides in how Blink processes and validates HTML elements when parsing web content. When a remote attacker crafts a specific HTML page containing carefully constructed elements, the browser's validation system fails to properly identify and reject potentially harmful constructs. This occurs because the validation logic does not adequately cover all possible HTML element combinations or attributes that could be used to exploit the rendering engine's processing pathways. The vulnerability demonstrates a classic case of insufficient input validation where the system assumes certain HTML constructs are safe without proper verification. This type of flaw is categorized under CWE-20, which addresses improper input validation, and represents a significant weakness in the browser's security architecture.
The operational impact of this vulnerability extends beyond simple rendering issues and presents substantial risks to user security and privacy. Remote attackers can leverage this flaw to bypass HTML validators that are designed to prevent malicious code injection or unauthorized content manipulation. The vulnerability could enable attackers to inject malicious scripts, manipulate page content, or potentially access sensitive user data through crafted HTML pages delivered via phishing attacks or compromised websites. This capability directly aligns with tactics described in the attack pattern taxonomy where adversaries exploit browser implementation flaws to achieve unauthorized access or privilege escalation. The vulnerability affects users who visit compromised websites or receive maliciously crafted emails with embedded HTML content, making it particularly dangerous in real-world scenarios.
Mitigation strategies for CVE-2020-6413 focus primarily on updating to the patched version of Google Chrome, specifically version 80.0.3987.87 or later, which includes corrected validation logic for HTML parsing. Organizations should implement comprehensive patch management processes to ensure all user devices receive the security update promptly. Browser security configurations should also be reviewed to ensure that additional protective measures are in place, including content security policies and sandboxing mechanisms that can provide defense in depth. Network administrators should consider implementing web filtering solutions that can detect and block suspicious HTML content before it reaches end users. The vulnerability serves as a reminder of the critical importance of maintaining up-to-date browser software and implementing layered security approaches that can protect against both known and emerging threats in the browser security landscape.