A recently patched vulnerability in JetBrains TeamCity, a widely used continuous integration and continuous delivery platform, is being actively exploited by hackers. According to the US Cybersecurity and Infrastructure Security Agency (CISA), threat actors have started targeting organizations using TeamCity On-Premises versions, putting sensitive data and systems at risk.
TeamCity is a central component of enterprise workflows, collaboration, and development practices, providing automated software building and deployment capabilities. The vulnerability, tracked as CVE-2026-63077 with a CVSS score of 9.8, allows unauthenticated attackers to achieve remote code execution (RCE) via HTTP/S requests. This means that hackers can bypass authentication checks and execute arbitrary operating system commands with the privileges of the TeamCity server process.
The flaw affects all TeamCity On-Premises versions and was addressed in patches released for versions 2025.11.7 and 2026.1.3, as well as a security patch plugin for version 2017.1+. JetBrains warned that organizations should apply these patches to their TeamCity On-Premises deployments as soon as possible.
CISA added CVE-2026-63077 to its Known Exploited Vulnerabilities (KEV) catalog last week, urging federal agencies to patch the issue within three days. While there is no public information on attacks exploiting this vulnerability yet, it’s essential for all organizations using TeamCity On-Premises versions to take immediate action.
The exploitation of this vulnerability highlights the importance of regular security updates and patches in preventing cyber threats. In today’s interconnected world, a single vulnerable system can put entire networks at risk. As teams continue to rely on software development platforms like TeamCity, it’s crucial that they stay vigilant and prioritize security best practices, including keeping their systems up-to-date with the latest patches.
In light of this development, organizations using TeamCity On-Premises versions should take the following steps:
* Immediately apply the relevant patch or update for their version
* Review their system configurations to ensure they are not exposing any additional vulnerabilities
* Consider implementing additional security measures, such as monitoring and logging, to detect potential attacks
By taking proactive steps to address this vulnerability, organizations can minimize the risk of a successful attack and protect their sensitive data.
Source: SecurityWeek — 2026-08-06