CVE-2025-54531 is a path traversal vulnerability classified under CWE-23 found in JetBrains TeamCity versions before 2025.07, specifically on Windows platforms during the plugin unpacking process. Path traversal vulnerabilities occur when an application improperly sanitizes user-supplied file paths, allowing attackers to escape the intended directory structure and access or overwrite arbitrary files on the filesystem. In this case, the vulnerability enables an attacker with high privileges and requiring user interaction to craft malicious plugin packages that, when unpacked by TeamCity, can write files outside the designated plugin directory. This can lead to arbitrary file overwrite or creation, potentially allowing attackers to modify configuration files, inject malicious code, or disrupt the build process. The vulnerability requires local access with elevated privileges (PR:H) and user interaction (UI:R), and the attack vector is local (AV:L). The scope is changed (S:C), meaning the vulnerability can affect resources beyond the initially vulnerable component. The impact on confidentiality and integrity is high (C:H, I:H), while availability impact is low (A:L). Although no known exploits are reported in the wild, the vulnerability poses a significant risk due to TeamCity's role in continuous integration and deployment pipelines, which are critical for software development and delivery. The lack of available patches at the time of publication necessitates immediate attention from affected organizations.

The vulnerability can lead to unauthorized file system access and modification, compromising the confidentiality and integrity of sensitive build artifacts, configuration files, and potentially credentials stored on the system. Attackers could inject malicious code into the build pipeline, leading to supply chain compromises affecting downstream software products. The availability impact is limited but could manifest as disruption of build services if critical files are overwritten or corrupted. Organizations relying on TeamCity for continuous integration and deployment are at risk of compromised software integrity and potential data breaches. The requirement for high privileges and user interaction limits remote exploitation but does not eliminate risk, especially in environments where multiple users have elevated access or where social engineering could trigger the vulnerability. The widespread use of TeamCity in software development organizations globally amplifies the potential impact.

1. Upgrade TeamCity to version 2025.07 or later once patches are released by JetBrains to address this vulnerability. 2. Until patches are available, restrict plugin installation permissions strictly to trusted administrators to minimize the risk of malicious plugin unpacking. 3. Implement strict file system monitoring and integrity checks on directories used by TeamCity for plugin unpacking to detect unauthorized file modifications. 4. Employ application whitelisting and endpoint protection solutions to prevent execution or loading of unauthorized files. 5. Enforce the principle of least privilege for users with access to TeamCity servers, limiting elevated privileges only to essential personnel. 6. Educate administrators about the risks of social engineering attacks that could lead to user interaction triggering exploitation. 7. Consider isolating TeamCity build agents and servers in segmented network zones to reduce lateral movement in case of compromise. 8. Regularly audit and review plugin sources and verify digital signatures where applicable to ensure plugin authenticity.