FlowiseAI Flowise CVE-2026-8027

The attacker must possess valid authentication credentials to access FlowiseAI Flowise (PR:L in CVSS vector). The vulnerability specifically affects manipulation of userId, organizationId, workspaceId, and email parameters passed to the User Controller Handler component-deployments that do not expose or use these parameters in accessible APIs may have reduced attack surface. The flaw does not require special configuration or non-default settings; it exists in the default behavior of the affected component. Multi-tenant or multi-user deployments are at higher risk than isolated single-user instances, as the authorization bypass enables horizontal privilege escalation. No user interaction is required (UI:N).

The CVSS 4.3 score with PR:L (requires low privilege authentication) and AV:N (network-exploitable) reflects a moderate but real threat. The AC:L (low complexity) vector indicates straightforward exploitation once authenticated. The confidentiality impact (C:L) is confirmed but integrity and availability are unaffected (I:N/A:N), limiting scope to information disclosure. While the CVSS score is moderate, the practical risk depends on deployment context: in multi-tenant SaaS deployments or organizations with shared Flowise instances, this could allow lateral privilege escalation or cross-tenant data access. The low EPSS does not negate real-world risk because this is a privilege boundary violation requiring authentication, not a widespread automated attack vector. No KEV status or public exploit confirmation has been provided, suggesting either targeted or under-researched exploitation. The availability of a GitHub Gist reference suggests proof-of-concept may exist but was not independently verified. Organizations using Flowise in shared or multi-user environments should prioritize this for remediation; single-user deployments face lower practical risk.

An authenticated user (Alice) with a valid account in a shared Flowise instance crafts an API request to the User Controller Handler, replacing the userId parameter in her own workspace request with the userId of another user (Bob). Due to insufficient authorization checks, the server returns Bob's profile data or workspace contents. Alice repeats this with different organizationId and email parameters to enumerate and access other organizations' configurations and data.