Active exploitation of a software development platform within Australia
Published Sources: ASD ACSC
What is affected, what to do
Listen notification_important Alert Active exploitation of a software development platform within Australia Alert on actively exploited vulnerabilities affecting TeamCity On-Premise servers. Assess exposure and apply vendor mitigations for CVE 2026 63077 (Critical, 9.8). error Alert Status: High help High alert rating A high alert is a cyber security vulnerability where people should act quickly (within 48 hours).
The available sources name no fixed version. Check the vendor guidance in the references below.
Not sure whether and how you are affected? Ask a question about this vulnerability
Metrics
—
Priority
No value is available for this vulnerability.
—
CVSS v3
No value is available for this vulnerability.
—
EPSS score
No value is available for this vulnerability.
Show all metrics
- Severity
- Not rated
Priority (0–325)
The priority score is a consolidated metric that condenses several individual signals into a single, action-guiding ranking: technical severity (CVSS), exploitation likelihood (EPSS), known-exploited status (KEV) and the context of the affected asset. The aim is to answer the only truly important question in vulnerability management: what first?
Read in glossary- 24.14 Methodology
Exploit maturity
An exploit is code or a technique that specifically uses a concrete vulnerability to force unintended behaviour — such as executing code or escalating privileges. It is the tool that turns a theoretical flaw into a practical attack.
Read in glossary- no public PoC known
KEV status
The KEV catalogue is a list maintained by the US authority CISA of vulnerabilities for which active exploitation in the wild has been confirmed. It answers not the question „how severe?“ but „is it already being attacked?“ — thereby sharply prioritising patching.
Read in glossary- —
- Published
Classification under NIS2 and CRA
Rule-based classification from exploitation status and severity. It does not replace a case-by-case assessment.
NIS2
NIS2 is EU Directive (EU) 2022/2555 to raise the level of cybersecurity across the Union. It substantially broadens obligations compared with the first NIS directive: more sectors, mandatory risk management, staged reporting duties and personal accountability of senior management.
Read in glossary- Handle the vulnerability in regular vulnerability handling under Art. 21(2)(e) NIS2.
CRA
The CRA is EU Regulation (EU) 2024/2847 setting horizontal cybersecurity requirements for „products with digital elements“ — from industrial controllers and software to connected consumer devices. For the first time manufacturers must ensure security across the entire product lifecycle, handle vulnerabilities and provide security updates.
Read in glossary- From 11.12.2027, Annex I Part II CRA requires manufacturers of affected products with digital elements to handle vulnerabilities without delay and provide security updates.
ISO/IEC 27001
ISO/IEC 27001 is the internationally leading standard for an information security management system (ISMS). It describes a risk-based, process-oriented framework to systematically plan, implement, review and improve information security.
Read in glossary- Control A.8.8, management of technical vulnerabilities: assess relevance to your systems, plan remediation and keep evidence.
Description
Listen notification_important Alert Active exploitation of a software development platform within Australia Alert on actively exploited vulnerabilities affecting TeamCity On-Premise servers. Assess exposure and apply vendor mitigations for CVE 2026 63077 (Critical, 9.8). error Alert Status: High help High alert rating A high alert is a cyber security vulnerability where people should act quickly (within 48 hours). There are generally no mitigating factors available, and the impact is widespread amongst customers. Impacts are estimated to be lower than a critical alert. High alerts refer to vulnerabilities that might affect Australia. Published 24 Aug 2026 Last reviewed 24 Aug 2026 | <button class="page-header__print-link" type="button" aria-expanded="false" aria-controls="page-header-print-menu" data-header-menu-trigger > print Print page Print page <button class="page-header__share-link" type="button" aria-expanded="false" aria-controls="page-header-share-menu" data-header-menu-trigger > email Email or share link chevron_right <a href="https://twitter.com/intent/tweet?text=https%3A%2F%2Fwww.cyber.gov.au%2Falert%2Factive-exploitation-of-a-software-development-platform-within-australia" class="page-header__icon-link" role="menuitem" target="_blank" rel="noopener noreferrer" data-share-network="x" aria-label="Share on X" > <a href="https://www.facebook.com/sharer/sharer.php?u=https%3A%2F%2Fwww.cyber.gov.au%2Falert%2Factive-exploitation-of-a-software-development-platform-within-australia"e=https%3A%2F%2Fwww.cyber.gov.au%2Falert%2Factive-exploitation-of-a-software-development-platform-within-australia" class="page-header__icon-link" role="menuitem" target="_blank" rel="noopener noreferrer" data-share-network="facebook" aria-label="Share on Facebook" > <a href="https://www.linkedin.com/feed/?shareActive=true&text=https%3A%2F%2Fwww.cyber.gov.au%2Falert%2Factive-exploitation-of-a-software-development-platform-within-australia" class="page-header__icon-link" role="menuitem" target="_blank" rel="noopener noreferrer" data-share-network="linkedin" aria-label="Share on LinkedIn" > <a href="mailto:?subject=Active%20exploitation%20of%20a%20software%20development%20platform%20within%20Australia&body=https%3A%2F%2Fwww.cyber.gov.au%2Falert%2Factive-exploitation-of-a-software-development-platform-within-australia" class="page-header__icon-link" role="menuitem" data-share-network="email" data-share-subject="Active exploitation of a software development platform within Australia" aria-label="Share by email" > <button class="page-header__print-share-link" type="button" aria-expanded="false" aria-controls="page-header-mobile-menu" data-header-menu-trigger > Print or share chevron_right Print page <img data-component-id="cybergovau:image" class="cga-image page-header__image cga-image--lazy cga-image--banner cga-image--responsive" loading="lazy" data-image-style="banner" src="/themes/custom/cybergovau/assets/images/page-header.svg" alt="" > This alert is relevant to all Australian organisations that utilise the TeamCity On-Premises server. This alert is intended for a technical audience. Background The Australian Signals Directorate's Australian Cyber Security Centre (ASD's 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. 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. This 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 ASD's 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 a 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. Where to get help Organisations that have been impacted, suspect impact or require advice and assistance can contact us via 1300 CYBER1 (1300 292 371) .