Executive brief
Hatchet is a workflow orchestration platform; its gRPC Dispatcher service is responsible for managing worker connections and job assignments across tenants. A missing authorization check allows any tenant with a valid API token to modify or disconnect workers belonging to other tenants on the same instance, disrupting job processing for competing teams or customers. This is particularly severe in Hatchet Cloud where multiple independent customers share infrastructure.
Technical details
The vulnerability is a missing authorization check (CWE-862) in two Dispatcher RPC methods: UpsertWorkerLabels and Unsubscribe. These methods accept a worker_id in the request body but fail to validate that the worker belongs to the caller's tenant, even though they read the caller's tenant from the bearer-token context. An attacker with any valid tenant-scoped API token (e.g., an OWNER token from a newly created tenant or a leaked CI token) can craft gRPC requests targeting worker UUIDs from other tenants. While UUID guessing is required, successful exploitation allows the attacker to overwrite worker affinity labels (causing job misrouting) or forcibly disconnect workers (causing denial of service). The vulnerability affects Hatchet versions 0.40.0 through 0.91.1 and is patched in 0.91.2.
Affected products
- Hatchet Hatchet 0.40.0 to 0.91.1
Timeline
- 2026-06-30: disclosed
- 2026-08-28: patched: Fixed in version 0.91.2