{"id":"CVE-2026-84298","aliases":["GHSA-9q4h-f4x5-ffq8","GO-2026-6561"],"url":"https://o3.security/vulnerability/CVE-2026-84298","summary":"Hatchet: Cross-tenant durable callback payload disclosure in Hatchet V1 Dispatcher","details":"## Summary\n\nThe V1 `DurableTask` stream handler registers worker-supplied durable task external IDs in an in-memory callback routing map before verifying that the authenticated tenant owns the task. If the tenant-scoped ownership check fails, the handler logs the error and continues, but the map entry persists until the stream closes.\n\nDurable callback delivery resolves the destination stream by `task_external_id` only, without checking tenant identity. As a result, a tenant A worker that knows a tenant B durable task external UUID can hold its stream open and receive tenant B's durable callback result payload when the callback is delivered on the same dispatcher process.\n\n## Impact\n\nThis advisory requires an attacker to successfully guess a durable task external UUID belonging to another tenant. Durable task external IDs are generated with `uuid.New()` (UUIDv4) and are not enumerable across tenants, so exploitation requires prior knowledge of a target task UUID through an out-of-band channel. Thus, while the following environments are impacted, there is an extremely low probability it would be exploited. \n\n**Who is impacted.** Any Hatchet deployment that hosts more than one tenant on the same instance:\n- Hatchet Cloud (multi-tenant SaaS) \n- Self-hosted Hatchet with multiple internal teams / business units sharing one instance\n- Any deployment where a single tenant's API token can be obtained by an attacker\n\nSingle-tenant self-hosted deployments are unaffected in practice (the \"victim\" and \"attacker\" tenants would be the same).","published":"2026-09-21T15:47:50.252Z","modified":"2026-10-21T03:00:28.688482989Z","cvss":{"score":3.1,"severity":"LOW","vector":"CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":null,"affectedPackages":[{"ecosystem":"Go","name":"github.com/hatchet-dev/hatchet","fixedVersion":"0.95.3"}],"fix":{"url":"https://github.com/hatchet-dev/hatchet/commit/9555bfdd1e97f61d25e614ccaa107c5fb7dc4976","label":"hatchet-dev/hatchet@9555bfd"},"references":[{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/84xxx/CVE-2026-84298.json"},{"type":"ADVISORY","url":"https://github.com/hatchet-dev/hatchet/security/advisories/GHSA-9q4h-f4x5-ffq8"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-84298"},{"type":"FIX","url":"https://github.com/hatchet-dev/hatchet/commit/9555bfdd1e97f61d25e614ccaa107c5fb7dc4976"},{"type":"PACKAGE","url":"https://github.com/hatchet-dev/hatchet"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-10-21T03:00:28.688482989Z"}}