Hatchet: Cross-tenant durable callback payload disclosure in Hatchet V1 DispatcherGHSA-9q4h-f4x5-ffq8
LOWFix: hatchet-dev/hatchet@9555bfdGHSA-9q4h-f4x5-ffq8 is a low-severity (CVSS 3.1) CWE-639 vulnerability in github.com/hatchet-dev/hatchet. A fix is available for github.com/hatchet-dev/hatchet — see the affected versions and patch details below.
Exploitation Status
No confirmed exploitation observed yet
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for GHSA-9q4h-f4x5-ffq8.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
GHSA-9q4h-f4x5-ffq8 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 394,803 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
github.com/hatchet-dev/hatchetReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.
Description
Summary
The 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.
Durable 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.
Impact
This 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.
Who is impacted. Any Hatchet deployment that hosts more than one tenant on the same instance:
- Hatchet Cloud (multi-tenant SaaS)
- Self-hosted Hatchet with multiple internal teams / business units sharing one instance
- Any deployment where a single tenant's API token can be obtained by an attacker
Single-tenant self-hosted deployments are unaffected in practice (the "victim" and "attacker" tenants would be the same).
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐹Go | github.com/hatchet-dev/hatchet | all versions | 0.95.3go get github.com/hatchet-dev/hatchet@v0.95.3 |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/hatchet-dev/hatchet, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/hatchet-dev/hatchet to 0.95.3 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-9q4h-f4x5-ffq8 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.
Frequently Asked Questions
Is GHSA-9q4h-f4x5-ffq8 in your dependencies?
Find it across Go, including transitive dependencies.