{"cve":"CVE-2026-40933","nvd":{"published":"2026-04-21T22:16:19.383","modified":"2026-10-26T22:10:00.163","status":"Analyzed","description":"Flowise is a drag & drop user interface to build a customized large language model flow. Prior to 3.1.0, due to unsafe serialization of stdio commands in the MCP adapter, an authenticated attacker can add an MCP stdio server with an arbitrary command, achieving command execution. The vulnerability lies in a bug in the input sanitization from the “Custom MCP” configuration in http://localhost:3000/canvas - where any user can add a new MCP, when doing so - adding a new MCP using stdio, the user can add any command, even though your code have input sanitization checks such as validateCommandInjection and validateArgsForLocalFileAccess, and a list of predefined specific safe commands - these commands, for example \"npx\" can be combined with code execution arguments (\"-c touch /tmp/pwn\") that enable direct code execution on the underlying OS. This vulnerability is fixed in 3.1.0.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H","score":9.9},"cwes":["CWE-78"],"references":["https://github.com/FlowiseAI/Flowise/security/advisories/GHSA-c9gw-hvqq-f33r","https://www.ox.security/blog/mcp-supply-chain-advisory-rce-vulnerabilities-across-the-ai-ecosystem","https://www.ox.security/blog/the-mother-of-all-ai-supply-chains-critical-systemic-vulnerability-at-the-core-of-the-mcp","https://github.com/FlowiseAI/Flowise/security/advisories/GHSA-c9gw-hvqq-f33r"],"products":["flowiseai:flowise"],"source":"nvd","synced_at":"2026-10-26T22:26:44.656832877+00:00"},"epss":{"cve":"CVE-2026-40933","score":0.11964,"percentile":0.9609,"date":"2026-10-26"},"kev":null,"osv":[{"id":"GHSA-c9gw-hvqq-f33r","url":"https://osv.dev/vulnerability/GHSA-c9gw-hvqq-f33r","summary":"Flowise: Authenticated RCE Via MCP Adapters","modified":"2026-04-16T21:41:26.849953Z","packages":[{"ecosystem":"npm","name":"flowise","purl":"pkg:npm/flowise","ranges":["<3.1.0"],"fixed":["3.1.0"]},{"ecosystem":"npm","name":"flowise-components","purl":"pkg:npm/flowise-components","ranges":["<3.1.0"],"fixed":["3.1.0"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}