CVE-2025-54535 is a medium-severity vulnerability identified in JetBrains TeamCity, a widely used continuous integration and continuous delivery (CI/CD) server. The vulnerability arises from the use of weak hashing algorithms for password reset and email verification tokens in versions of TeamCity prior to 2025.07. Specifically, the tokens generated for these critical authentication-related processes rely on cryptographic hashes that do not meet current security standards, classified under CWE-328 (Reversible One-Way Hash). Weak hashing algorithms can be susceptible to collision attacks or preimage attacks, allowing an attacker to potentially predict or forge tokens. This undermines the security of password reset and email verification workflows, which are essential for user account integrity and access control. The CVSS v3.1 base score is 5.8, indicating a medium severity level. The vector string (CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:L/I:N/A:N) shows that the vulnerability is remotely exploitable over the network without requiring privileges or user interaction, and it affects confidentiality with a scope change, but does not impact integrity or availability. Although no known exploits are currently reported in the wild, the vulnerability's presence in a critical authentication mechanism makes it a significant concern for organizations relying on TeamCity for their software development pipelines.

For European organizations, the impact of this vulnerability could be substantial, especially for those heavily dependent on TeamCity for their DevOps processes. Exploitation could allow attackers to compromise password reset and email verification tokens, potentially enabling unauthorized access to user accounts or the ability to manipulate account recovery processes. This could lead to unauthorized access to build configurations, source code, or deployment pipelines, risking intellectual property theft, insertion of malicious code, or disruption of software delivery. Given the nature of CI/CD environments, a compromised TeamCity server could serve as a pivot point for further attacks within the organization's network. The confidentiality impact is moderate, but the potential for lateral movement and supply chain compromise elevates the risk. European organizations in sectors such as finance, healthcare, and critical infrastructure, which rely on secure software development practices, could face regulatory and reputational consequences if this vulnerability is exploited.

To mitigate this vulnerability, European organizations should prioritize upgrading TeamCity to version 2025.07 or later, where the weak hashing algorithms have been replaced with cryptographically strong alternatives. If immediate upgrade is not feasible, organizations should implement compensating controls such as enforcing multi-factor authentication (MFA) for all TeamCity user accounts to reduce the risk of unauthorized access via token compromise. Additionally, monitoring and logging password reset and email verification activities can help detect suspicious behavior. Organizations should also review and harden their CI/CD pipeline security posture by restricting network access to TeamCity servers, applying the principle of least privilege for user accounts, and conducting regular security audits. Finally, educating developers and DevOps teams about secure token management and the importance of timely patching is critical to prevent exploitation.