CVE-2026-58057 Flowise - Custom MCP Environment Variable Denylist Bypass via Case Sensitivity
Authenticated users can bypass environment variable denylists via case sensitivity on Windows to execute arbitrary code in the Flowise server.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2026-58057?
CVE-2026-58057 is a low-severity vulnerability in Flowiseai Flowise, published on 28 Jun 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official 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.
Weakness: CWE-178
Which versions are affected by CVE-2026-58057?
It affects 1 product.
Products include Flowiseai Flowise.
How do I fix CVE-2026-58057?
No fix has been published for CVE-2026-58057 yet. Limit exposure of the affected software until one is available.
Is CVE-2026-58057 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-58057 exists.
Public exploit code: 1 Exploit-DB entry and 1 proofs of concept on GitHub.
Other vulnerabilities in Flowiseai Flowise
- CVE-2025-71338 Flowise through 2.2.7 - Arbitrary File Write to Remote Code Execution via document-store API
- CVE-2026-40933 Flowise: Authenticated RCE Via MCP Adapters
- CVE-2025-61913 Flowise is vulnerable to arbitrary file read, arbitrary file write
- CVE-2025-59528 Flowise has Remote Code Execution vulnerability
- CVE-2026-52098 Code injection in n/a
Sources
Also known as GHSA-rqqr-m697-6jq3.