CVE-2026-46480: Flowise: Evaluator create+update mass-assignment allows cross-workspace evaluator takeover

Synopsis

A mass-assignment vulnerability in Flowise, the drag-and-drop LLM workflow builder, allows an authenticated attacker to take over evaluators belonging to other workspaces by sending crafted create or update requests. The vulnerability 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 availability impact on the target evaluator resource. HarborGuard tracks this advisory and will make a patched-image rebuild available the moment an upstream fix version is published.

HarborGuard Coverage

Exploit Conditions

• Network reachabilityRequired

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

• AuthenticationRequired

  A low-privilege account is sufficient; the attacker does not need administrative credentials to send the crafted evaluator payload.

• Victim interactionNot required

  No action from another user or workspace member is needed to complete the attack.

• Attack complexityDetail

  Base exploit logic is condition-free and reliable, though the CVSS AT:P token indicates that specific deployment conditions (such as multi-workspace configuration being active) must be present for the cross-workspace takeover to succeed.

Blast Radius

• Reads evaluator configurations and associated data belonging to other workspaces.
• Overwrites or tampers with evaluator definitions in victim workspaces, corrupting LLM evaluation results.
• Denies availability of targeted evaluators, disrupting automated model evaluation pipelines in affected workspaces.
• Provides no confirmed lateral reach into systems outside the Flowise instance itself, based on the CVSS scope tokens.