CVE-2025-53821 is an Open Redirect vulnerability (CWE-601) identified in the LabRedesCefetRJ WeGIA web application, an open-source web manager primarily targeting Portuguese language users and charitable institutions. The vulnerability exists in versions prior to 3.4.5 and specifically affects the 'control.php' endpoint. This endpoint accepts a 'nextPage' parameter that is intended to redirect users to a specified URL after certain actions. However, due to insufficient validation or sanitization of this parameter, an attacker can supply an arbitrary URL, causing the application to redirect users to potentially malicious external sites. This uncontrolled redirection can be exploited in phishing attacks, where users are tricked into clicking links that appear to originate from a trusted source but lead to malicious websites. The vulnerability has a CVSS v3.1 base score of 4.7, categorized as medium severity. The vector indicates that the attack can be performed remotely (AV:N) with low attack complexity (AC:L), requires no privileges (PR:N), but does require user interaction (UI:R). The scope is changed (S:C), meaning the vulnerability affects resources beyond the initially vulnerable component. The impact affects integrity minimally (I:L) but does not affect confidentiality or availability. No known exploits are currently reported in the wild. The issue was addressed in version 3.4.5 of WeGIA, which includes a fix to properly validate or restrict the 'nextPage' parameter to prevent arbitrary redirection.

For European organizations using WeGIA, particularly charitable institutions and entities operating in Portuguese-speaking communities within Europe, this vulnerability poses a moderate risk. The primary impact is on user trust and potential phishing attacks leveraging the open redirect to redirect users to malicious sites that could harvest credentials or distribute malware. While the vulnerability does not directly compromise system confidentiality or availability, it can be used as a stepping stone in social engineering attacks or combined with other vulnerabilities for more severe consequences. Organizations relying on WeGIA for managing web content or user workflows may see reputational damage if users fall victim to redirected phishing scams. Additionally, regulatory frameworks such as GDPR emphasize protecting users from phishing and fraud, so exploitation could lead to compliance issues. The risk is heightened in environments where users are less security-aware or where the application is integrated into critical user-facing portals.

To mitigate this vulnerability, European organizations should immediately upgrade WeGIA installations to version 3.4.5 or later, where the issue is patched. If immediate upgrading is not feasible, organizations should implement strict input validation on the 'nextPage' parameter, restricting redirects to a whitelist of trusted internal URLs only. Web application firewalls (WAFs) can be configured to detect and block suspicious redirect patterns targeting the vulnerable endpoint. Additionally, organizations should educate users about the risks of clicking on unexpected links, especially those that appear to redirect through trusted domains. Monitoring logs for unusual redirect requests can help identify attempted exploitation. Finally, integrating multi-factor authentication (MFA) can reduce the impact of phishing attacks that might leverage this vulnerability to steal credentials.