Hackers Exploit Marimo RCE to Steal AWS Credentials and Reach Bastion Host in 8 Seconds
Attackers exploited pre-auth RCE CVE-2026-39987 in Marimo notebooks to steal AWS credentials and SSH into a bastion host in eight seconds.
Sysdig Threat Research Team documented an intrusion abusing CVE-2026-39987, an unauthenticated RCE in Marimo's terminal WebSocket endpoint affecting versions up to 0.20.4 and fixed in 0.23.0. The attacker harvested AWS credentials from the host environment and Redis backend, queried AWS Secrets Manager to retrieve an SSH private key, and authenticated to an internet-facing SSH bastion host just eight seconds after opening the WebSocket session. Human-operated custom tooling, not an AI agent, executed the full exploit-to-lateral-movement chain.
65