CVE-2006-6091 in GrimBB
Summary
by MITRE
Cross-site scripting (XSS) vulnerability in Grim Pirate GrimBB before 2006_11_21 allows remote attackers to inject arbitrary web script or HTML via unspecified vectors.
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Analysis
by VulDB Data Team • 04/28/2026
The vulnerability identified as CVE-2006-6091 represents a critical cross-site scripting flaw within the Grim Pirate GrimBB forum software prior to the 2006_11_21 release. This type of vulnerability falls under the CWE-79 category, which specifically addresses cross-site scripting attacks where malicious scripts can be injected into web applications. The vulnerability exists in the input validation mechanisms of the GrimBB software, creating an exploitable condition that allows remote attackers to execute arbitrary web scripts or HTML code within the context of other users' browsers. The unspecified vectors suggest that the flaw could potentially be exploited through multiple entry points within the application's user input handling processes.
The technical implementation of this XSS vulnerability demonstrates a fundamental failure in the software's sanitization of user-supplied data. When users submit content through various interface elements such as posts, comments, or profile information, the GrimBB application fails to properly validate or escape the input before rendering it in web pages. This allows attackers to craft malicious payloads that, when executed, can perform actions such as stealing session cookies, redirecting users to malicious sites, or defacing the forum content. The remote nature of the attack means that no local access is required, making the vulnerability particularly dangerous as it can be exploited from anywhere on the internet.
The operational impact of this vulnerability extends beyond simple data corruption or content modification. The ability for remote attackers to inject malicious scripts creates a persistent threat vector that can compromise user sessions and potentially lead to broader system compromise. Users who visit infected forum pages become victims of the attack, with their browsers executing the injected code without their knowledge. This vulnerability particularly affects community-driven platforms where user-generated content is prevalent, as it undermines the trust users place in the forum environment. The impact is amplified when considering that forum administrators may not immediately detect such attacks, allowing malicious content to persist and affect multiple users over extended periods.
Security mitigation strategies for this vulnerability should focus on implementing robust input validation and output encoding mechanisms. The most effective approaches include sanitizing all user input through proper escaping techniques before rendering content, implementing content security policies to restrict script execution, and ensuring that all web applications properly encode data when displaying user-supplied information. Organizations should also consider implementing web application firewalls to detect and block suspicious input patterns. The remediation process requires updating to the patched version of GrimBB released after 2006_11_21, as well as conducting thorough security audits of the application's input handling procedures. This vulnerability serves as a reminder of the critical importance of proper input validation in web applications and aligns with ATT&CK technique T1566 which covers the exploitation of web applications through various injection attacks including XSS. The incident highlights the necessity of continuous security testing and the implementation of defense-in-depth strategies to protect against such persistent threats in web environments.