Checkmarx Confirms Dark Web Leak of Data Taken From Internal GitHub Repository

Checkmarx said data stolen during its March supply chain intrusion has been published on the dark web, with investigators tracing the exposure to a corporate GitHub repository accessed during the initial attack. The company said the affected repository was part of its developer environment, not its customer production environment, and that current evidence indicates customer data was not stored there and remains unaffected.

The disclosure follows reports that LAPSUS$ listed Checkmarx on its leak site and claimed to possess source code, an employee database, API keys, and MongoDB and MySQL credentials. Checkmarx said it has locked down access to the repository and is continuing forensic analysis to determine exactly what source code or internal documentation was exfiltrated, while warning that the incident is part of a broader supply chain attack chain that also involved tampered GitHub Actions workflows, Open VSX plugins, and other developer tooling tied to the earlier compromise.