Pre-authenticated RCE in Marimo exploited within 10 hours of advisory
Updated: 16.04.2026 19:58
· First: 10.04.2026 10:37
· 📰 3 src / 3 articles
A pre-authenticated remote code execution (RCE) vulnerability in Marimo, tracked as CVE-2026-39987 (CVSS 9.3), was exploited in the wild within hours of public disclosure, enabling attackers to gain full PTY shells on exposed instances via the unauthenticated /terminal/ws WebSocket endpoint. The flaw, affecting Marimo versions prior to 0.23.0, initially led to rapid, human-driven exploitation campaigns focused on credential theft. Recent attacks have expanded to deploy a new NKAbuse malware variant hosted on Hugging Face Spaces, using typosquatted repositories to evade detection and establish persistent remote access. Additional exploitation activity includes sophisticated lateral movement, such as reverse-shell techniques and database enumeration, indicating a shift toward multi-stage attacks beyond initial credential harvesting. Threat actors validated the vulnerability within seconds, harvested credentials in under three minutes, and conducted reconnaissance from 125 IP addresses within the first 12 hours post-disclosure. GitHub assessed the flaw with a critical CVSS score of 9.3, and Marimo developers confirmed impact on instances deployed as editable notebooks or exposed via --host 0.0.0.0 in edit mode.