Flowise before version 3.1.0 contains a path traversal flaw in its Faiss and SimpleStore vector store implementations. An authenticated user can supply an unsanitized basePath value, causing the service to write data to any filesystem location reachable by the Flowise process. The unsanitized input permits the attacker to place arbitrary files on the host, which could lead to code execution if the target environment allows script execution or to data exfiltration of sensitive host files. The weakness is a classic file‑path traversal flaw, identified as CWE‑22.

All installations of Flowise running a version earlier than 3.1.0 are vulnerable, regardless of deployment size or custom configuration. The flaw resides in the core vector store components and is not limited to specific operating systems.

The CVSS score of 4.9 indicates moderate severity, and the EPSS score of less than 1% suggests a very low likelihood of widespread exploitation at present. The vulnerability is only reachable by users with a valid API token, so broad public exposure is not possible. Once authenticated, an attacker can write files to arbitrary locations, which may enable script execution or malicious data exfiltration depending on the host environment. The lack of listing in CISA’s KEV catalog further reduces the perceived exploitation pressure at this time.