JetBrains TeamCity is a widely used continuous integration and build management software, typically employed by developers and DevOps teams to automate processes such as code compiling, testing, and deployment. It facilitates numerous operations within software development workflows, aiming for higher efficiency and quality in product releases. TeamCity supports various programming languages and is compatible with numerous build tools, making it adaptable to different environments. The software is known for its extensive version control support, enabling streamlined collaboration on different projects within teams. JetBrains TeamCity is designed for use in enterprises seeking to optimize their software development life cycle.
The vulnerability in question allows remote code execution due to improper handling of agent polling protocols, enabling attackers to execute arbitrary code remotely. This vulnerability does not require authentication, making it particularly dangerous and easy to exploit. If not patched, attackers could completely compromise the affected systems, leading to potential access to sensitive information or further network penetration. It exists in older versions of the software and necessitates immediate attention for maintaining system integrity. Remote code execution poses significant risks, particularly when orchestrated against systems critical to operations.
The remote code execution vulnerability primarily occurs via the agent polling protocol, which is exploited by sending crafted requests that leverage deserialization vulnerabilities. During these interactions, attackers can insert malicious payloads without needing authenticated access. The specific endpoints involved typically relate to the "/app/agents/" path, where the software's handling of serialized data can be subverted. The vulnerability hinges greatly on improper parameter validation, allowing crafted data to be processed in a way that triggers unintended commands within the application.
Should malicious actors exploit this vulnerability, they could potentially gain unrestricted access to the system running the vulnerable version of TeamCity. This could lead to unauthorized manipulation, data theft, or full control over the application and its processes. The ability to execute arbitrary code could allow attackers to perform malicious activities such as espionage, data modification, and lateral movement within an organization's network, causing widespread disruption. Organizations may face data breaches or service interruptions, with long-term effects on operational trust and data integrity.
REFERENCES
- https://blog.jetbrains.com/teamcity/2026/07/cve-2026-63077/
- https://www.rapid7.com/blog/post/etr-cve-2026-63077-critical-unauthenticated-remote-code-execution-in-jetbrains-teamcity/
- https://nvd.nist.gov/vuln/detail/CVE-2026-63077
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-63077
- Upgrade JetBrains TeamCity to the latest version to mitigate the vulnerability.
- Regularly audit and monitor your TeamCity server logs for unexpected activities.
- Implement robust network monitoring to detect attempts to exploit vulnerable endpoints.
- Restrict access to the TeamCity server to trusted IPs through firewall rules and proper configurations.
- Regularly review and update agent configurations to ensure they adhere to security best practices.
- Educate your team about security best practices and the risks of unpatched software.
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