CVE-2025-54529 is a Cross-Site Request Forgery (CSRF) vulnerability identified in JetBrains TeamCity, a popular continuous integration and build management system. This vulnerability affects versions of TeamCity released before 2025.07 and specifically targets the external OAuth login integration feature. CSRF vulnerabilities occur when an attacker tricks an authenticated user into submitting a forged request to a web application, potentially causing unauthorized actions without the user's consent. In this case, the flaw lies in the external OAuth login process, which is used to authenticate users via third-party identity providers. An attacker could exploit this vulnerability by crafting a malicious request that, when executed by a logged-in user, could perform unintended actions within TeamCity under the user's privileges. The CVSS v3.1 base score is 3.7, indicating a low severity level. The vector string (AV:N/AC:H/PR:L/UI:R/S:U/C:L/I:L/A:N) shows that the attack requires network access, high attack complexity, low privileges, and user interaction, and it impacts confidentiality and integrity to a limited extent without affecting availability. No known exploits are currently reported in the wild, and no official patches have been linked yet. The vulnerability is classified under CWE-352, which corresponds to CSRF issues. Given TeamCity's role in managing build pipelines and potentially sensitive code repositories, this vulnerability could allow attackers to manipulate build configurations or access sensitive information if successfully exploited.

For European organizations using JetBrains TeamCity, this vulnerability poses a risk primarily to the integrity and confidentiality of their build and deployment processes. An attacker exploiting this CSRF flaw could potentially perform unauthorized actions such as modifying build configurations, triggering builds with malicious parameters, or accessing sensitive project information. While the impact on availability is negligible, the integrity compromise could lead to the injection of malicious code into software builds or unauthorized access to proprietary source code. This is particularly concerning for organizations in regulated industries (e.g., finance, healthcare, critical infrastructure) where software integrity is paramount. The requirement for user interaction and low privileges reduces the likelihood of widespread exploitation, but targeted attacks against privileged users (e.g., build administrators) remain a concern. Additionally, since OAuth integration is involved, organizations relying on external identity providers for authentication could see an increased attack surface if this vulnerability is exploited. Overall, the threat could undermine trust in automated build pipelines and introduce risks in software supply chain security within European enterprises.

To mitigate this vulnerability effectively, European organizations should: 1) Immediately upgrade JetBrains TeamCity to version 2025.07 or later once the patch is officially released, as this version addresses the CSRF issue in OAuth login integration. 2) Until patching is possible, restrict access to the TeamCity server to trusted networks and users, minimizing exposure to potential attackers. 3) Implement strict Content Security Policy (CSP) headers and SameSite cookie attributes to reduce the risk of CSRF attacks. 4) Review and harden OAuth integration configurations, ensuring that redirect URIs and state parameters are properly validated to prevent unauthorized OAuth flows. 5) Educate users, especially those with build administration privileges, about the risks of clicking on suspicious links while authenticated to TeamCity. 6) Monitor TeamCity logs for unusual activities such as unexpected build triggers or configuration changes that could indicate exploitation attempts. 7) Consider deploying Web Application Firewalls (WAFs) with rules tailored to detect and block CSRF attack patterns targeting the TeamCity OAuth endpoints. These targeted measures go beyond generic advice by focusing on the specific OAuth integration vector and build system context.