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.
- CVE-2026-39987 pre-auth RCE in Marimo WebSocket endpoint, fixed in 0.23.0
- Only eight seconds from initial shell to SSH bastion authentication
- Stolen AWS credentials used to pull SSH key from Secrets Manager
- Human-operated tooling executed the attack chain at machine speed
- CVEs
- CVE-2026-39987
Vulnerabilities mentioned
All| CVE | Vulnerability | CVSS | EPSS | Signals | Published |
|---|---|---|---|---|---|
| CVE-2026-39987 | Unauthenticated Remote Code Execution in Marimo Python Notebook | 9.3 | 100% | KEVPoC ×8 | KEV |
From the original article
3 min read at cybersecuritynews.com
Threat actors have been observed exploiting a critical remote code execution vulnerability in the Marimo notebook platform to steal AWS credentials and authenticate to an SSH bastion host within eight seconds. The attack, documented by the Sysdig Threat Research Team, abused CVE-2026-39987, a pre-authentication remote code execution flaw affecting Marimo versions up to and including […]
By Abinaya · cybersecuritynews.com
A short excerpt; the article and its images belong to the publisher. Summary, key facts and assessment above are AI-written from the article and can be wrong.