GHSA-8x7x-83cf-c3pg Hatchet allows cross-tenant write/DoS to other tenants' workers via Dispatcher gRPC UpsertWorkerLabels and Unsubscribe

• Go github.com/hatchet-dev/hatchet: >= 0.40.0, < 0.91.2 → fixed in 0.91.2

Summary A cross-tenant write / DoS vulnerability in the Hatchet `Dispatcher` gRPC service allows any holder of a normal tenant-scoped API token (the lowest credential Hatchet issues — an `OWNER` of a brand-new tenant) to overwrite the affinity labels of, or disconnect from the dispatcher, any worker UUID belonging to any other tenant on the same Hatchet instance. The two affected RPCs — `Dispatcher/UpsertWorkerLabels` and `Dispatcher/Unsubscribe` — read the caller's tenant from the bearer-token context only for analytics and response shaping, and never use it to authorise the `worker_id` from the request body. Impact This CVE requires the attacker to successfully guess the target UUID. Who is impacted. Any Hatchet deployment that hosts more than one tenant on the same instance: • Hatchet Cloud (multi-tenant SaaS) — every tenant is exposed to every other tenant. • Self-hosted Hatchet with multiple internal teams / business units sharing one instance — each team is exposed to every other team on the box. • Any deployment where a single tenant's API token can be obtained by an attacker (e.g. a leaked low-privilege CI token from a single tenant). One token is enough to attack every other tenant on the same instance. Single-tenant self-hosted deployments are unaffected in practice (the "victim" and "attacker" tenants would be the same).