CVE-2026-73654: Trigger.dev: Prototype pollution via run metadata operations → process-wide cross-tenant DoS

The run-metadata update endpoint PUT /api/v1/runs/:runId/metadata applies client-supplied “operations” by passing the attacker-controlled operation.key straight into new JSONHeroPath(operation.key).set(newMetadata, value) (packages/core/src/v3/runMetadata/operations.ts:22-23), with no prototype-pollution guard (@jsonhero/path@^1.0.21 does not reject __proto__/constructor/prototype).

A request with key: "$.__proto__.polluted" sets Object.prototype.polluted in the webapp process. Because every plain object then inherits that property, it corrupts unrelated code process-wide and across tenants — including Prisma query building and the Prometheus metrics client — causing query failures, broken authentication for other tenants’ workers, and an uncaughtException (denial of service). Only a normal, low-privilege environment API key is required (one request).