ASD warns of active exploitation of development platform in Australia

The Australian Signals Directorate (ASD) has issued an alert with high status related to the TeamCity On-Premises server development environment from JetBrains.

The Australian Cyber Security Centre (ACSC) has observed active exploitation of a vulnerability affecting TeamCity On-Premises servers within Australia. TeamCity is a continuous integration and continuous deployment (CI/CD) server to automate the processes of building, testing and deploying software.

A vulnerability in the system (CVE 2026-63077) may allow an unauthenticated attacker with HTTP(S) access to a TeamCity server to bypass authentication checks and execute arbitrary operating system commands. The vulnerability affects all TeamCity On-Premises versions.

ASD’s ACSC has no information to indicate that a specific industry or sector is being targeted.

Mitigation advice

The ACSC advises organisations to ensure the following:

• Review networks and environments for use of vulnerable versions of the TeamCity On-Premises server.
• Review the need to continue to have the interface exposed to the internet.
• Review the mitigation advice on the vendor support page.
• If TeamCity Server is managed by a third party, such as an MSP or Enterprise IT provider, you should contact that provider to ensure the products have been patched and are being monitored for suspicious activity.
• Apply patches as soon as practicable, if required.
• Monitor for suspicious activity. Indicators of Compromise (IoC) have been released by the vendor, which may assist in detecting malicious activity.
• If suspicious activity is detected, notify ASD’s ACSC.
   

Organisations that have been impacted, suspect impact or require advice and assistance can contact the ACSC via 1300 CYBER1 (1300 292 371).

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