CVE-2026-46479: Flowise: Evaluation create+update mass-assignment allows cross-workspace evaluation takeover

Synopsis

Mass-assignment vulnerability in Flowise, the drag-and-drop LLM flow builder, allows an authenticated attacker to take over evaluations belonging to other workspaces. The flaw is reachable over the network and requires only a low-privilege account; no victim interaction is needed. Successful exploitation gives the attacker full read, write, and denial-of-service capability over the targeted evaluation objects. A patched-image rebuild at version 3.1.2 is available on HarborGuard for affected environments.

HarborGuard Coverage

Exploit Conditions

• Network reachabilityRequired

  The attacker must reach the Flowise API over the network; the service must be exposed to the attacker's network path.

• AuthenticationRequired

  A low-privilege Flowise account is sufficient; no admin or elevated role is needed to trigger the mass-assignment flaw.

• Victim interactionNot required

  No action from another user or admin is needed; the attacker exploits the endpoint directly.

• Attack complexityDetail

  Exploitation requires a specific precondition to be met (AT:P), such as the target evaluation existing in a reachable workspace context, but the attack itself is otherwise condition-free once that precondition holds.

Blast Radius

• The attacker reads evaluation data belonging to other workspaces, including any stored prompts, outputs, and test results.
• The attacker overwrites or corrupts evaluation records in foreign workspaces, tampers with scoring results, and injects malicious content into evaluation datasets.
• The attacker deletes or disrupts evaluation objects, causing denial of service for teams relying on those evaluations in their LLM development workflows.
• Cross-workspace access breaks tenant isolation, meaning a compromise by any low-privilege user can affect every workspace whose evaluations are reachable through the mass-assignment endpoint.