CVE-2025-59113 identifies a security weakness in Windu CMS version 4.1 related to improper restriction of excessive authentication attempts (CWE-307). The CMS attempts to mitigate brute-force attacks by using a client-side parameter named 'loginError' to track the number of failed login attempts or impose timeouts. However, this approach is fundamentally flawed because the attempt count and timeout state are not maintained on the server side. An attacker can reset or manipulate the 'loginError' parameter, effectively bypassing the brute-force protection mechanism. This allows unlimited automated login attempts without triggering any lockout or delay, increasing the risk of credential guessing or brute-force attacks. The vulnerability requires no authentication or user interaction and can be exploited remotely over the network. The vendor was notified early but has not disclosed detailed vulnerability information or provided patches. Only version 4.1 has been confirmed vulnerable through testing, but other versions may also be affected. The CVSS v4.0 score is 6.9 (medium severity), reflecting the network attack vector, low attack complexity, and no privileges or user interaction required, but limited impact on confidentiality and integrity since only partial information disclosure or account compromise is possible. No known exploits are currently reported in the wild. The vulnerability highlights a common security design flaw where client-side controls are trusted for critical security functions, which should always be enforced server-side.

For European organizations using Windu CMS, this vulnerability poses a significant risk of unauthorized access through brute-force attacks. Attackers can repeatedly attempt to guess user credentials without being blocked or delayed, potentially leading to account compromise, unauthorized data access, or privilege escalation if administrative accounts are targeted. This can result in data breaches, defacement, or further exploitation of the compromised CMS environment. The impact is particularly critical for organizations relying on Windu CMS for public-facing websites, e-commerce platforms, or internal portals containing sensitive information. Additionally, successful exploitation could undermine trust in the affected services and lead to regulatory compliance issues under GDPR if personal data is exposed. Since no patches are currently available, the risk remains until mitigations are implemented. The lack of server-side enforcement also means that traditional network defenses may not detect or prevent these brute-force attempts effectively, increasing the threat surface.

European organizations should immediately implement server-side brute-force protections independent of the CMS's client-side controls. This includes deploying rate limiting on login endpoints to restrict the number of attempts per IP address or user account within a defined time window. Implement account lockout policies after a configurable number of failed login attempts, combined with CAPTCHA challenges to prevent automated attacks. Monitoring and alerting on unusual login activity or repeated failed attempts can help detect ongoing attacks. Where possible, enforce multi-factor authentication (MFA) to reduce the risk of compromised credentials leading to account takeover. Organizations should also consider web application firewalls (WAFs) configured to detect and block brute-force patterns targeting Windu CMS login pages. Regularly review and update CMS versions and monitor vendor communications for patches or updates addressing this vulnerability. If feasible, conduct internal penetration testing to verify the effectiveness of implemented mitigations. Finally, educate users on strong password practices and the risks of credential reuse.