Ravie LakshmananMay 29, 2026Vulnerability / Artificial Intelligence
An unknown threat actor has been observed using a large language model (LLM) agent to conduct post-compromise actions after obtaining initial access following the exploitation of a publicly-accessible Marimo network using a recently disclosed vulnerability.
"The attacker compromised an internet-reachable Marimo notebook via CVE-2026-39987, extracted two cloud credentials from the compromised host, replayed them through a fanned-out egress pool to retrieve an SSH private key from AWS Secrets Manager, and used that key to drive eight short SSH sessions against a downstream SSH bastion server," Sysdig said.
"The bastion phase exfiltrated the schema and full contents of an internal PostgreSQL database in under two minutes."
CVE-2026-39987 refers to a critical pre-authenticated remote code execution vulnerability impacting all versions of Marimo prior to and including 0.20.4. It allows an unauthenticated attacker to execute arbitrary system commands. The issue was addressed in version 0.23.0, released last month.
