CVE-2026-91931: Flowise before 3.1.4 Remote Code Execution via Custom MCP npx

Severity: high (CVSS 8.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-09-15 · updated 2026-09-23
Weakness: CWE-78

Description

Flowise before 3.1.4 contains a remote code execution vulnerability in the Custom MCP node that allows authenticated attackers to execute arbitrary code by supplying npx package names in the mcpServerConfig parameter. Attackers can invoke npx with attacker-controlled npm packages to execute code on the Flowise server.

Affected products

FlowiseAI Flowise: before 3.1.4 — fixed in 3.1.4

How to fix

Upgrade to a fixed version: FlowiseAI Flowise 3.1.4. Check the vendor advisory for mitigations.

References

https://github.com/FlowiseAI/Flowise/security/advisories/GHSA-vcwp-f9rq-3887
https://www.vulncheck.com/advisories/flowise-before-3.1.4-remote-code-execution-via-custom-mcp-npx
https://github.com/FlowiseAI/Flowise/security/advisories/GHSA-vcwp-f9rq-3887

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