Critical severity9.8CISA KEVNVD Advisory· Published Apr 9, 2026· Updated Apr 23, 2026
CVE-2026-39987
CVE-2026-39987
Description
marimo is a reactive Python notebook. Prior to 0.23.0, Marimo has a Pre-Auth RCE vulnerability. The terminal WebSocket endpoint /terminal/ws lacks authentication validation, allowing an unauthenticated attacker to obtain a full PTY shell and execute arbitrary system commands. Unlike other WebSocket endpoints (e.g., /ws) that correctly call validate_auth() for authentication, the /terminal/ws endpoint only checks the running mode and platform support before accepting connections, completely skipping authentication verification. This vulnerability is fixed in 0.23.0.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
marimoPyPI | < 0.23.0 | 0.23.0 |
Affected products
2Patches
Vulnerability mechanics
References
8- github.com/marimo-team/marimo/commit/c24d4806398f30be6b12acd6c60d1d7c68cfd12anvdPatchWEB
- github.com/marimo-team/marimo/pull/9098nvdIssue TrackingPatchWEB
- github.com/marimo-team/marimo/security/advisories/GHSA-2679-6mx9-h9xcnvdExploitMitigationVendor AdvisoryWEB
- www.sysdig.com/blog/marimo-oss-python-notebook-rce-from-disclosure-to-exploitation-in-under-10-hoursnvdExploitThird Party AdvisoryWEB
- github.com/advisories/GHSA-2679-6mx9-h9xcghsaADVISORY
- nvd.nist.gov/vuln/detail/CVE-2026-39987ghsaADVISORY
- www.cisa.gov/known-exploited-vulnerabilities-catalogghsaWEB
- www.cisa.gov/known-exploited-vulnerabilities-catalognvdUS Government ResourceWEB
News mentions
6- Researchers Build Self-Replicating AI Worm That Operates Entirely on Local, Open-Weight ModelsThe Hacker News · Jun 9, 2026
- Nobody needs Mythos or 0-days to build a chaos-causing computer worm – free open source models work just fineThe Register Security · Jun 4, 2026
- Attackers Use LLM Agent for Post-Exploitation After Marimo CVE-2026-39987 ExploitThe Hacker News · May 29, 2026
- Hackers Use LLM Agent to Move From Marimo RCE to Internal Database in Four PivotsCyber Security News · May 28, 2026
- 13th April – Threat Intelligence ReportCheck Point Research · Apr 13, 2026
- CISA Adds One Known Exploited Vulnerability to CatalogCISA Alerts