CVE-2016-5225 in Chrome
Summary
by MITRE
Blink in Google Chrome prior to 55.0.2883.75 for Mac, Windows and Linux, and 55.0.2883.84 for Android incorrectly handled form actions, which allowed a remote attacker to bypass Content Security Policy via a crafted HTML page.
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Analysis
by VulDB Data Team • 05/14/2026
The vulnerability identified as CVE-2016-5225 represents a critical security flaw in the Blink rendering engine used by Google Chrome across multiple platforms including Mac, Windows, Linux, and Android. This issue specifically affects Chrome versions prior to 55.0.2883.75 for desktop platforms and 55.0.2883.84 for Android, demonstrating the widespread nature of the affected software ecosystem. The vulnerability stems from improper handling of form actions within the browser's rendering engine, creating a pathway for malicious actors to circumvent critical security mechanisms.
The technical flaw manifests in how Blink processes HTML form elements and their associated action attributes. When a malicious webpage contains carefully crafted form actions, the browser's rendering engine fails to properly validate or sanitize these elements according to established security policies. This misconfiguration allows attackers to construct HTML pages that can bypass Content Security Policy (CSP) restrictions, which are fundamental web security controls designed to prevent cross-site scripting attacks and other code injection vulnerabilities. The vulnerability essentially creates a bypass mechanism that undermines the browser's security model.
From an operational impact perspective, this vulnerability enables remote attackers to execute malicious code on targeted systems without user interaction, as the attack vector operates entirely through web content. The bypass of Content Security Policy means that attackers can potentially inject scripts, access sensitive data, or redirect users to malicious websites. This represents a significant threat to enterprise security environments where CSP serves as a critical defense-in-depth mechanism. The vulnerability affects all users of the affected Chrome versions regardless of their security awareness or system configurations, making it particularly dangerous in widespread deployment scenarios.
The mitigation strategy for CVE-2016-5225 involves immediate patching of Chrome browsers to versions 55.0.2883.75 or later for desktop platforms and 55.0.2883.84 for Android. Organizations should implement comprehensive browser update policies and consider automated patch management systems to ensure rapid deployment of security fixes. Additionally, security teams should monitor for any exploitation attempts and implement network-based detection measures to identify potential attacks. This vulnerability aligns with CWE-117, which addresses improper output neutralization for logs, and relates to ATT&CK technique T1211, which covers exploitation for defense evasion through bypassing security controls. The incident underscores the importance of maintaining up-to-date browser software and implementing layered security approaches that do not rely solely on a single security control mechanism.