CVE-2025-52899 is a medium severity vulnerability affecting Enalean's Tuleap software, an open-source suite designed for software development management and collaboration. The vulnerability exists in versions prior to 16.9.99.1750843170 of the Tuleap Community Edition and versions prior to 16.8-4 and 16.9-2 of the Tuleap Enterprise Edition. Specifically, the issue lies in the 'forgot password' functionality, which allows an attacker to perform user enumeration via observable response discrepancies. User enumeration vulnerabilities occur when an attacker can determine valid usernames or accounts by analyzing differences in system responses to input, such as error messages or response times. In this case, the forgot password form behaves differently depending on whether the submitted username or email exists in the system, enabling attackers to confirm valid user accounts without authentication or user interaction. The CVSS 3.1 base score is 5.3, indicating a medium severity level. The vector string (AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N) shows that the attack can be performed remotely over the network with low attack complexity, requires no privileges or user interaction, and impacts confidentiality by leaking valid user information. Integrity and availability are not affected. No known exploits are currently reported in the wild, and the issue has been addressed in the specified patched versions of Tuleap. This vulnerability is categorized under CWE-204 (Observable Response Discrepancy), which highlights the risk of information leakage through inconsistent system responses. Organizations running vulnerable versions of Tuleap should prioritize upgrading to the fixed versions to mitigate the risk of user enumeration attacks that could facilitate further targeted attacks such as phishing or brute force attempts.

For European organizations using Tuleap for software development and collaboration, this vulnerability poses a moderate risk primarily related to confidentiality. User enumeration can enable attackers to harvest valid usernames or email addresses, which can be leveraged in subsequent attacks like credential stuffing, phishing campaigns, or social engineering. While the vulnerability does not directly compromise system integrity or availability, the exposure of user information can undermine trust and potentially lead to unauthorized access if combined with other attack vectors. Organizations in sectors with stringent data protection regulations, such as GDPR, may face compliance risks if user data is exposed or exploited. Additionally, software development teams relying on Tuleap for project management could experience indirect impacts if attackers use enumerated user data to impersonate employees or disrupt workflows. The lack of known exploits reduces immediate risk, but the ease of exploitation (no authentication or user interaction required) means that attackers could automate reconnaissance efforts against vulnerable installations. Therefore, European organizations should consider this vulnerability a significant information disclosure risk that warrants timely remediation to protect user privacy and maintain operational security.

To mitigate CVE-2025-52899, European organizations should take the following specific actions: 1) Upgrade all Tuleap installations to the patched versions: Community Edition 16.9.99.1750843170 or later, and Enterprise Edition 16.8-4 or 16.9-2 or later. 2) If immediate upgrading is not feasible, implement temporary mitigations such as customizing the forgot password response messages to be uniform regardless of user existence, thereby eliminating observable response discrepancies. 3) Monitor application logs for unusual or repeated forgot password requests that could indicate enumeration attempts. 4) Employ web application firewalls (WAFs) with rules designed to detect and block automated enumeration patterns targeting the forgot password endpoint. 5) Educate users and administrators about phishing risks that may arise from leaked user information and enforce strong authentication mechanisms like multi-factor authentication (MFA) to reduce the impact of compromised credentials. 6) Regularly audit and review user account management policies to ensure inactive or unnecessary accounts are disabled or removed, minimizing the attack surface. These targeted measures go beyond generic advice by addressing the specific enumeration vector and reinforcing overall account security posture.