CVE-2026-46441: Flowise: Mass Assignment in Assistant Update Endpoint Allows Cross-Workspace Resource Reassignment

Synopsis

A mass assignment vulnerability in Flowise allows authenticated users to overwrite server-controlled fields, including workspaceId, on the assistant update endpoint. The flaw is reachable over the network and requires only a low-privilege account; no additional victim interaction is needed. Successful exploitation lets an attacker reassign assistants to arbitrary workspaces, breaking tenant isolation and exposing or corrupting resources belonging to other workspace tenants. HarborGuard tracks this advisory and will make a patched-image rebuild available the moment an upstream fix is published.

HarborGuard Coverage

Exploit Conditions

• Network reachabilityRequired

  The vulnerable endpoint is exposed over the network, so an attacker must be able to reach the Flowise service via HTTP.

• AuthenticationRequired

  A low-privilege authenticated account is sufficient; no administrative privileges are needed to reach the vulnerable endpoint.

• Victim interactionNot required

  The attacker sends a crafted API request directly; no victim action or social engineering is involved.

• Attack complexityDetail

  Attack complexity is rated High, meaning the attacker may need to satisfy specific environmental or timing conditions, such as knowledge of target workspace identifiers, to complete the reassignment.

Blast Radius

• Reads assistant configurations and associated LLM flow data belonging to other workspace tenants, breaching cross-tenant confidentiality.
• Reassigns assistants across workspace boundaries, corrupting resource ownership and disrupting expected tenant isolation in multi-workspace deployments.
• Manipulates server-controlled metadata fields such as createdDate and updatedDate, undermining audit trails and data integrity for affected resources.