CVE-2017-6511 in FineCMS
Summary
by MITRE
andrzuk/FineCMS before 2017-03-06 is vulnerable to a reflected XSS in index.php because of missing validation of the action parameter in application/classes/application.php.
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Analysis
by VulDB Data Team • 05/05/2025
The vulnerability identified as CVE-2017-6511 affects the andrzuk/FineCMS content management system prior to version 2017-03-06, representing a critical reflected cross-site scripting flaw that exposes end users to potential security risks. This vulnerability exists within the application's handling of user input through the index.php script, specifically in the application/classes/application.php file where the action parameter lacks proper validation mechanisms. The flaw enables attackers to inject malicious scripts into web pages viewed by other users, creating a persistent threat vector that can be exploited across multiple sessions and user interactions.
The technical implementation of this vulnerability stems from insufficient input sanitization and validation processes within the FineCMS framework. When the application processes requests through the index.php endpoint, it fails to properly validate or sanitize the action parameter received from user input. This parameter is directly incorporated into the application's response without adequate filtering or encoding, allowing malicious actors to craft specially crafted URLs that contain XSS payloads. The vulnerability manifests when users navigate to maliciously constructed URLs containing script code within the action parameter, which then gets executed in the context of other users' browsers.
The operational impact of this reflected XSS vulnerability extends beyond simple script execution, potentially enabling attackers to perform session hijacking, steal sensitive cookies, redirect users to malicious websites, or perform actions on behalf of authenticated users. Attackers can leverage this vulnerability to exploit user sessions, access administrative interfaces, modify content, or exfiltrate sensitive data from the affected system. The reflected nature of the vulnerability means that malicious payloads must be delivered through external means such as phishing emails, compromised websites, or social engineering campaigns, as the attack requires users to interact with the malicious link. This characteristic makes the vulnerability particularly dangerous in environments where users frequently click on links from untrusted sources.
Security practitioners should implement comprehensive input validation and output encoding measures to address this vulnerability, ensuring that all user-supplied parameters undergo proper sanitization before being processed or displayed. The fix requires developers to validate the action parameter against a whitelist of allowed values or implement proper HTML encoding of all user-controllable input before rendering it in web responses. Organizations should also consider implementing content security policies and regularly updating their CMS installations to prevent exploitation of known vulnerabilities. This vulnerability aligns with CWE-79 which specifically addresses cross-site scripting flaws, and represents a clear violation of secure coding practices that should be addressed through proper input validation and output encoding mechanisms. The ATT&CK framework categorizes this vulnerability under the T1059.008 technique for scripting languages, specifically targeting web application interfaces and user input handling processes that fail to properly validate or sanitize incoming data.