Ethical Hacking News
JetBrains has patched a critical TeamCity flaw that allows unauthenticated code execution on affected on-premise servers, enabling attackers to execute arbitrary commands with server privileges. This vulnerability is rated at 9.8 on the CVSS scale and poses significant risks to server security. Organizations must upgrade to the latest version or implement additional security measures to minimize exploitation.
Pierluigi Paganini reports a critical vulnerability in JetBrains' TeamCity software, affecting its security and integrity. The identified flaw (CVE-2026-63077) allows unauthenticated attackers to execute arbitrary commands with server privileges. The Common Vulnerabilities and Exposures system assigns a CVSS score of 9.8, indicating an extremely severe threat to server security. The vulnerability can bypass authentication checks and access sensitive data, credentials, configurations, and compromise CI/CD pipelines. Server exposure via HTTP(S) protocols makes them vulnerable without prior knowledge or access. JetBrains recommends upgrading to the latest version and implementing additional security measures, such as restricting network access and running TeamCity on dedicated hosts.
Pierluigi Paganini, a renowned cybersecurity expert and author of Security Affairs, has recently reported on a critical vulnerability affecting JetBrains' TeamCity software, a popular integrated development environment (IDE) for software developers. The identified flaw, tracked as CVE-2026-63077, poses a significant threat to the security and integrity of affected servers, allowing unauthenticated attackers to execute arbitrary commands.
The Common Vulnerabilities and Exposures (CVE) system has assigned a CVSS score of 9.8 to this vulnerability, indicating that it is considered extremely severe in terms of its potential impact on server security. This rating is based on the vulnerability's severity, attack vector, and privileges required to exploit it. In essence, an attacker can bypass authentication checks and execute arbitrary operating system commands with TeamCity server privileges, potentially accessing sensitive data, credentials, configurations, altering server settings, and compromising CI/CD pipelines.
The vulnerability affects servers exposed via HTTP(S) protocols, which makes them vulnerable to exploitation without requiring any prior knowledge or access. The agent polling protocol is the primary attack vector that allows an attacker to bypass authentication checks and execute arbitrary OS commands with TeamCity server privileges. This means that attackers can potentially hijack sensitive data, credentials, and configurations, as well as alter server settings and compromise CI/CD pipelines.
To address this vulnerability, JetBrains has released security updates for TeamCity On-Premises, which include patches for versions 2025.11.7 and 2026.1.3. These updates are available to organizations that cannot upgrade to the latest version immediately. The company also recommends implementing additional security measures, such as restricting network access, applying least-privilege configurations, and running TeamCity on dedicated hosts separated from build agents.
Furthermore, JetBrains has released a security patch plugin for affected versions of TeamCity. This plugin fixes only CVE-2026-63077 and can be installed on TeamCity 2017.1 and later. However, the company suggests that organizations should upgrade to the latest version as soon as possible to benefit from other security updates.
It is essential for organizations using TeamCity On-Premises to take immediate action to address this vulnerability. By following JetBrains' recommendations, such as upgrading to the latest version, restricting network access, and implementing least-privilege configurations, they can minimize the risk of exploitation and protect their servers from unauthorized access.
In conclusion, JetBrains has patched a critical TeamCity flaw that allows unauthenticated code execution on affected on-premise servers. This vulnerability is considered extremely severe due to its potential impact on server security. Organizations using TeamCity On-Premises must take immediate action to address this issue by upgrading to the latest version and implementing additional security measures.
Related Information:
https://www.ethicalhackingnews.com/articles/JetBrains-Patches-Critical-TeamCity-Flaw-Allowing-Server-Takeover-ehn.shtml
https://securityaffairs.com/196169/security/jetbrains-patches-cvss-9-8-teamcity-flaw-allowing-server-takeover.html
https://nvd.nist.gov/vuln/detail/CVE-2026-63077
https://www.cvedetails.com/cve/CVE-2026-63077/
Published: Tue Jul 28 07:08:14 2026 by llama3.2 3B Q4_K_M
