Description
Flowise before 3.1.3 validates Custom MCP stdio environment variables against a denylist using a case-sensitive comparison, so on Windows, where environment names are case-insensitive, supplying 'node_options' bypasses the NODE_OPTIONS denylist entry. An authenticated user who can configure a Custom MCP node can thereby inject NODE_OPTIONS --require and execute arbitrary code in the Flowise server context.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Flowise | Flowise | < 3.1.3 | 3.1.3 |
Public exploits
Exploit or proof-of-concept code for this vulnerability is publicly available, which lowers the bar for attackers. Treat it as a reason to patch sooner.
Exploit-DB 1
- Flowise 3.1.3 - arbitrary code execution EDB-52623 · webapps · Jul 7, 2026
GitHub 1 repository
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CerberusMrXi/Flowise-CVE-2026-58057-exploit ★ 1 · Jul 23, 2026
Flowise Windows RCE exploit for CVE-2026-58057. Bypasses environment variable validation via case-sensitive flaw. Uses node_options to inject arbitrary code through MCP stdio. Supports reverse shell,…
Sources: PoC-in-GitHub, Metasploit Framework, Exploit-DB — updated daily. Only links are listed; no exploit code is hosted here.
Advisories 1
- WID-SEC-2026-2106 Flowise: Schwachstelle ermöglicht Umgehen von Sicherheitsvorkehrungen BSI CERT-Bund (WID) · Jun 28, 2026
References
- Proof of Concept exploit third-party-advisory
- Fix (PR #6471, 3.1.3) issue-tracking patch
- VulnCheck Advisory: Flowise - Custom MCP Environment Variable Denylist Bypass via Case Sensitivity third-party-advisory