CVE-2025-54531 is a high-severity path traversal vulnerability (CWE-23) affecting JetBrains TeamCity versions prior to 2025.07 on Windows platforms. The vulnerability arises during the plugin unpacking process, where insufficient validation of file paths allows an attacker with high privileges to craft a malicious plugin archive that, when unpacked, can write files outside the intended directory structure. This path traversal can lead to overwriting or creating arbitrary files on the host system. The CVSS v3.1 score of 7.7 reflects a high-impact vulnerability with local attack vector (AV:L), low attack complexity (AC:L), requiring high privileges (PR:H) and user interaction (UI:R). The scope is changed (S:C), indicating that the vulnerability can affect resources beyond the initially vulnerable component. The impact on confidentiality and integrity is high, as arbitrary file writes can lead to code execution, privilege escalation, or exposure of sensitive data. Availability impact is low but possible if critical files are overwritten. No known exploits are currently reported in the wild. The vulnerability is specific to Windows due to the path handling differences compared to other OSes. The lack of patch links suggests that a fix may be pending or recently released in version 2025.07 or later. Organizations using TeamCity on Windows should consider this vulnerability critical to address promptly, especially in environments where plugins are installed or updated frequently.

For European organizations, the impact of CVE-2025-54531 can be significant, particularly for those relying on JetBrains TeamCity for continuous integration and deployment pipelines. Exploitation could allow attackers with existing high-level access to escape plugin sandboxing and modify system files, potentially leading to privilege escalation, unauthorized code execution, or disruption of build and deployment processes. This could result in compromised software supply chains, data breaches, or operational downtime. Organizations in sectors with stringent compliance requirements (e.g., finance, healthcare, critical infrastructure) may face regulatory and reputational damage if this vulnerability is exploited. The requirement for high privileges and user interaction limits remote exploitation but does not eliminate risk in environments where insiders or attackers have gained elevated access. The Windows-specific nature means organizations running TeamCity on Windows servers are at direct risk, while Linux-based deployments are not affected by this particular flaw.

1. Immediate upgrade: Apply the official JetBrains TeamCity update to version 2025.07 or later where the vulnerability is fixed. 2. Plugin management: Restrict plugin installation and updates to trusted administrators only, minimizing the risk of malicious plugin introduction. 3. Access controls: Enforce strict access controls and least privilege principles on TeamCity servers, ensuring only necessary users have high privileges required to install plugins. 4. Monitoring and auditing: Implement file integrity monitoring on TeamCity server directories to detect unauthorized file changes, especially during plugin unpacking. 5. Network segmentation: Isolate TeamCity servers within secure network segments to limit exposure if compromised. 6. Incident response readiness: Prepare for rapid response in case of suspicious activity related to plugin installation or file system changes. 7. Vendor communication: Maintain close communication with JetBrains for timely patch releases and advisories. These steps go beyond generic advice by focusing on controlling plugin-related risks and monitoring file system integrity specific to this vulnerability.