GHSA-hjwc-26pj-v3pm

## Summary A low-privileged authenticated AgenticMail agent can enumerate another agent's pending/claimed tasks by supplying the target agent name to `GET /api/agenticmail/tasks/pending?assignee=<name>`. The returned task objects include the task IDs and payloads. The same task IDs can then be used with the capability-style task mutation endpoints (`/tasks/:id/claim`, `/tasks/:id/result`, `/tasks/:id/complete`, `/tasks/:id/fail`) to claim, complete, or fail tasks assigned to a different agent. Because ordinary authenticated agents can discover agent names through `GET /api/agenticmail/accounts/directory`, the task ID effectively stops being a secret capability. This turns the intended capability model into a cross-agent authorization bypass. ## Affected component Package: `@agenticmail/api` Observed version: `0.9.62` Repository: `agenticmail/agenticmail` Relevant code paths: - `packages/api/src/app.ts`: `createAuthMiddleware(...)` is mounted before `createAccountRoutes(...)` and `createTaskRoutes(...)`, so these routes are reachable by any valid bearer token. - `packages/api/src/routes/accounts.ts`: `GET /accounts/directory` is available to any authenticated user and returns agent names. - `packages/api/src/routes/tasks.ts`: `GET /tasks/pending?assignee=name` resolves arbitrary agent names and returns that agent's pending/claimed tasks. - `packages/api/src/routes/tasks.ts`: `/tasks/:id/claim`, `/tasks/:id/result`, `/tasks/:id/complete`, `/tasks/:id/fail`, and `/tasks/:id` do not check whether the authenticated caller is the task assignee, assigner, or otherwise authorized for the task. ## Impact An attacker only needs a valid agent API key. They can: 1. List agent names using `/accounts/directory`. 2. Query another agent's task queue using `/tasks/pending?assignee=<victimName>`. 3. Read sensitive task payloads intended for the victim agent. 4. Use the disclosed task ID to complete/fail/claim the victim's task or submit attacker-controlled results. ## Local