CVE-2025-54536 is a Cross-Site Request Forgery (CSRF) vulnerability identified in JetBrains TeamCity, a widely used continuous integration and build management system. This vulnerability affects versions of TeamCity prior to 2025.07 and specifically targets the GraphQL endpoint. CSRF vulnerabilities occur when an attacker tricks an authenticated user into submitting a malicious request to a web application, exploiting the user's active session without their consent. In this case, the GraphQL endpoint in TeamCity does not adequately verify the origin or authenticity of requests, allowing an attacker to potentially perform unauthorized actions by leveraging the victim's credentials. The CVSS 3.1 base score for this vulnerability is 5.4, indicating a medium severity level. The vector string (AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N) reveals that the attack can be performed remotely over the network without privileges or authentication, requires low attack complexity, and needs user interaction (such as clicking a malicious link). The impact affects confidentiality and integrity but does not affect availability. No known exploits are currently reported in the wild, and no official patches or mitigations have been linked yet. However, given the nature of TeamCity as a critical DevOps tool, exploitation could lead to unauthorized information disclosure and modification of build configurations or data through the GraphQL API. This vulnerability highlights the importance of implementing proper anti-CSRF protections, such as CSRF tokens or same-site cookies, especially on sensitive API endpoints like GraphQL that can perform state-changing operations.

For European organizations, the impact of this vulnerability can be significant, particularly for enterprises relying on JetBrains TeamCity for their software development lifecycle and continuous integration pipelines. Unauthorized actions via CSRF could lead to exposure of sensitive build information, leakage of proprietary code or configuration data, and unauthorized modification of build processes, potentially introducing malicious code or disrupting development workflows. This can undermine the integrity of software releases and damage organizational trust and compliance posture. Since TeamCity is often integrated with other development and deployment tools, a successful attack could cascade, affecting broader IT infrastructure. The medium severity score reflects that while the vulnerability requires user interaction, the lack of authentication requirements and network accessibility increase the risk. European organizations with remote or hybrid work environments may be more susceptible to social engineering attempts that facilitate CSRF attacks. Additionally, regulatory frameworks such as GDPR emphasize the protection of personal and corporate data, so any data leakage or unauthorized modification could have legal and financial repercussions.

To mitigate this vulnerability, European organizations should prioritize upgrading TeamCity to version 2025.07 or later once the patch is available from JetBrains. In the interim, organizations can implement several practical measures: 1) Restrict access to the TeamCity server and its GraphQL endpoint using network-level controls such as VPNs, IP whitelisting, or firewall rules to limit exposure to trusted users only. 2) Enforce strict Content Security Policy (CSP) headers and SameSite cookie attributes to reduce the risk of CSRF exploitation via browsers. 3) Educate users and developers about the risks of clicking on untrusted links or visiting suspicious websites while authenticated to TeamCity. 4) Monitor TeamCity logs and network traffic for unusual or unauthorized GraphQL requests that could indicate attempted exploitation. 5) If feasible, implement web application firewalls (WAF) with custom rules to detect and block CSRF attack patterns targeting the GraphQL endpoint. 6) Review and harden authentication and session management configurations to minimize session hijacking risks. These targeted mitigations go beyond generic advice by focusing on the specific attack vector and environment of TeamCity deployments.