Human Attacker Exploits Marimo RCE, Reaches SSH Bastion in Eight Seconds

Summary: Sysdig reported that a human operator pivoted from a vulnerable Marimo notebook to an SSH bastion host in eight seconds using a hand-written Python toolkit, with no AI agent involved. The operator exploited CVE-2026-39987 (CVSS 9.3), a pre-authentication remote code execution flaw in all Marimo versions, and over a nine-hour session issued more than 850 interactive commands, harvesting AWS Secrets Manager credentials and an SSH private key while avoiding a trap that every agentic threat actor profiled against the same CVE fell into.
Why it matters: The operator matched machine-speed exploitation on skill alone and evaded a trap that caught every AI-driven attacker tested against the same flaw, so defenses tuned to recognize automated tooling may not register a human who hand-rolls scripts in-session.

Read the original at The Hacker News ↗

Topics: Cloud Security
Mentions: CVE-2021-33044 CVE-2021-33045 CVE-2026-39987
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