CVE-2025-59455 is a medium-severity vulnerability identified in JetBrains TeamCity, a widely used continuous integration and continuous deployment (CI/CD) server. The vulnerability is classified under CWE-362, which corresponds to a race condition leading to a project isolation bypass. Specifically, in versions of TeamCity prior to 2025.07.2, a race condition flaw allows an attacker with limited privileges to bypass project isolation controls. This means that an attacker could potentially access or interfere with projects they should not have permissions for, violating the intended access boundaries within the TeamCity environment. The vulnerability does not require user interaction and can be exploited remotely over the network, but it demands a higher attack complexity (AC:H) and requires the attacker to have limited privileges (PR:L). The CVSS v3.1 base score is 4.2, reflecting a medium severity level, with impacts on confidentiality and integrity but no impact on availability. No known exploits are currently reported in the wild, and no official patches or mitigation links were provided at the time of publication. The race condition nature of the flaw suggests that exploitation might be non-trivial and timing-dependent, but successful exploitation could allow unauthorized access to project data or manipulation of project configurations, undermining the security model of TeamCity projects.

For European organizations relying on JetBrains TeamCity for their software development pipelines, this vulnerability poses a risk to the confidentiality and integrity of their build and deployment processes. Unauthorized access to project data could lead to exposure of sensitive source code, build artifacts, or configuration secrets, potentially enabling further attacks such as supply chain compromises or intellectual property theft. Integrity violations could result in unauthorized changes to build configurations or deployment pipelines, risking the introduction of malicious code or disruption of software delivery. Given the critical role of CI/CD systems in modern software development, exploitation could have cascading effects on operational security and compliance, especially in regulated industries prevalent in Europe such as finance, healthcare, and telecommunications. However, the requirement for limited privileges and the complexity of exploitation somewhat reduce the immediate risk. Organizations with strict access controls and monitoring may mitigate the likelihood of exploitation, but those with less mature security practices could be more vulnerable.

European organizations should prioritize upgrading JetBrains TeamCity installations to version 2025.07.2 or later as soon as the patch becomes available. In the interim, organizations should enforce strict access controls to limit the number of users with project-level privileges, minimizing the attack surface. Implementing robust monitoring and alerting for unusual access patterns or race condition exploitation attempts can help detect potential attacks early. Additionally, organizations should review and harden their CI/CD pipeline security policies, including segregating projects and enforcing the principle of least privilege. Employing network segmentation to restrict access to TeamCity servers and using multi-factor authentication for all users with elevated privileges can further reduce risk. Regular security audits and penetration testing focused on race conditions and access control bypasses in CI/CD environments are recommended to proactively identify and remediate similar vulnerabilities.