Flowise is a UI for creating language-model workflows. A mass-assignment flaw in the tool update endpoint lets an authenticated user set server-controlled attributes such as workspaceId, createdDate, and updatedDate. Because the server performs no validation or authorization on these fields, an attacker can reassign a tool to an arbitrary workspace. This allows a user to access, modify, or delete resources that belong to other tenants, effectively breaking isolation between workspaces. The weakness is listed as CWE-284 (Improper Authorization), CWE-639 (Authorization Bypass Through User-Controlled Key), and CWE-915 (Mass Assignment).

The affected product is Flowise by FlowiseAI, versions prior to 3.1.2 that have not been patched. Users deployed in multi-workspace environments with authentication are at risk.

The CVSS score is 7.6, indicating a high severity. EPSS is not available, so no estimated exploitation probability can be provided. The vulnerability is not listed in the CISA KEV catalog. The attack vector is inferred to be authenticated; an attacker must possess valid credentials and is able to target the tool update API. Once exploited, the attacker can reassign resources, compromising tenant isolation.