CVE-2016-6521 in Console
Summary
by MITRE
Cross-site request forgery (CSRF) vulnerability in Grails console (aka Grails Debug Console and Grails Web Console) 2.0.7, 1.5.10, and earlier allows remote attackers to hijack the authentication of users for requests that execute arbitrary Groovy code via unspecified vectors.
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Analysis
by VulDB Data Team • 05/14/2026
The CVE-2016-6521 vulnerability represents a critical cross-site request forgery flaw in Grails console applications that affects versions 2.0.7 and 1.5.10 and earlier. This vulnerability specifically targets the Grails Debug Console and Grails Web Console components which are commonly used for development and debugging purposes within Grails applications. The flaw allows remote attackers to exploit user authentication sessions and execute arbitrary Groovy code through unspecified attack vectors, potentially leading to complete system compromise. The vulnerability is particularly dangerous because it combines both authentication bypass capabilities with code execution privileges, creating a severe threat landscape for applications that expose these console interfaces.
The technical implementation of this CSRF vulnerability stems from insufficient validation of request origins and lack of proper anti-forgery token mechanisms within the Grails console interfaces. When users authenticate to the console, their session remains active and can be leveraged by attackers who craft malicious requests that appear legitimate to the application server. The vulnerability operates at the application layer where the console accepts requests without adequate verification of the request source or user intent, allowing attackers to construct malicious web pages or emails that, when visited by authenticated users, automatically submit requests to the vulnerable console. This flaw directly relates to CWE-352, which specifically addresses Cross-Site Request Forgery vulnerabilities in web applications, and aligns with ATT&CK technique T1203 which covers exploitation of web application vulnerabilities for privilege escalation and code execution.
The operational impact of this vulnerability extends beyond simple data theft or modification to encompass complete system compromise capabilities. Attackers who successfully exploit this vulnerability can execute arbitrary Groovy code within the context of the application server, potentially gaining access to sensitive data, modifying application behavior, or even escalating privileges to system-level access. The vulnerability is particularly concerning in development environments where console interfaces might be accessible in production systems or where administrators might not properly secure these interfaces. Organizations using Grails applications with exposed console interfaces face significant risk of unauthorized access, data breaches, and potential system infiltration. The attack surface is broad since these console interfaces are often enabled by default in development configurations and may remain active in production environments where proper security hardening has not been implemented.
Mitigation strategies for CVE-2016-6521 must address both the immediate vulnerability and broader security posture of Grails applications. Organizations should immediately disable or secure access to Grails console interfaces through proper authentication controls, network segmentation, and access restriction measures. The recommended approach includes implementing robust anti-forgery token mechanisms, validating request origins through proper referer headers or custom validation tokens, and ensuring that console interfaces are not accessible from untrusted networks. Additionally, organizations should implement proper network access controls to restrict access to these interfaces to authorized personnel only, and consider disabling console interfaces in production environments entirely. The vulnerability also highlights the importance of proper security configuration management and regular security assessments of development tools and frameworks, aligning with industry best practices for securing web applications and following ATT&CK framework guidance for preventing exploitation of web application vulnerabilities. Regular patching and updating of Grails framework components remains essential to prevent similar vulnerabilities from being exploited in the future.