EUVD-2026-319043

fkie_cve-2026-42572

Hatchet is a platform for orchestrating background tasks, AI agents, and durable workflows at scale. Prior to 0.83.39, a missing authorization directive on the GET /api/v1/stable/dags/tasks endpoint caused Hatchet's tenant-membership check to be skipped for this route. A user authenticated to any tenant on the same Hatchet instance could query the endpoint with another tenant's UUID and a DAG UUID belonging to that tenant, and receive task metadata for that DAG. This vulnerability is fixed in 0.83.39.

GHSA-55gc-6fmc-fpx9 — Hatchet affected by cross-tenant information disclosure in `listTasksByDAGIds`

Affected: Go: github.com/hatchet-dev/hatchet

## Summary

A missing authorization directive on the `GET /api/v1/stable/dags/tasks` endpoint caused Hatchet's tenant-membership check to be skipped for this route. A user authenticated to any tenant on the same Hatchet instance could query the endpoint with another tenant's UUID and a DAG UUID belonging to that tenant, and receive task metadata for that DAG.

This issue has been patched in **v0.83.39**. Hatchet Cloud has been patched and requires no action from users. Self-hosted users should upgrade.

## Impact

**Who is affected.** Multi-tenant Hatchet instances reachable by an attacker who can obtain an account on that instance. On Hatchet Cloud, account creation is open by default. On self-hosted instances, the API must be reachable by the attacker and the hostname known; instances deployed inside a VPC or with signup restricted are not exposed to arbitrary external actors.

**Prerequisites for exploitation.** An attacker needed:

1. An account on the target Hatchet instance. 2. The victim tenant's UUID. 3. At least one DAG UUID (`external_id`) belonging to that tenant.

The two UUIDs are not treated as secrets — they appear in URLs, API responses, audit logs, invitation flows, shared run links, and dashboard screenshots — but an attacker does need to learn them through some out-of-band channel before exploitation is possible.

**What could be disclosed.** For each child task of a targeted DAG, the endpoint returned:

- `display_name`, `action_id`, `step_id` - `workflow…

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EUVD-2026-319043

fkie_cve-2026-42572

GHSA-55gc-6fmc-fpx9 — Hatchet affected by cross-tenant information disclosure in `listTasksByDAGIds`