CVE-2026-84298: Hatchet Cross-tenant Durable Callback Payload Disclosure Vulnerability

LOW
Advisory Identifier: GHSA-9q4h-f4x5-ffq8
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CVSS 3.1
CWE-639 CWE-862
Published
Advisory Summary

CVE-2026-84298 is a LOW (CVSS 3.1) cross-tenant durable callback payload disclosure vulnerability (CWE-639: Authorization Bypass Through User-Controlled Key) affecting Hatchet libraries in the Go ecosystem. The issue involves cross-tenant durable callback payload disclosure in hatchet v1 dispatcher. Remediation is available by upgrading affected packages to version 0.95.3.

CVE-2026-84298 at a Glance

CVE Identifier CVE-2026-84298
GHSA Identifier GHSA-9q4h-f4x5-ffq8
Severity LOW
CVSS v3.1 Base Score 3.1
CWE Classification CWE-639: Authorization Bypass Through User-Controlled Key
Affected Product Hatchet
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 3.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N).

Attack Vector Network (AV:N)
Attack Complexity High (AC:H)
Privileges Required Low (PR:L)
User Interaction None (UI:N)
Scope Unchanged (S:U)
Confidentiality Low (C:L)
Integrity None (I:N)
Availability None (A:N)

How to Fix CVE-2026-84298

To remediate this vulnerability, upgrade all affected Hatchet dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

github.com/hatchet-dev/hatchet fixed: 0.95.3 
Upgrade github.com/hatchet-dev/hatchet to 0.95.3
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for github.com/hatchet-dev/hatchet

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-84298, inspect your project dependencies for Hatchet:

inspect dependencies for github.com/hatchet-dev/hatchet

Analyze the terminal output to locate any version of Hatchet in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 0.95.3), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-639: Authorization Bypass Through User-Controlled Key, where the system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data. In Hatchet, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

## 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).

CVE-2026-84298 Affected Hatchet Versions

1 component(s)
Fixed Versions:
0.95.3
Product / Package Ecosystem Affected Versions Fixed Version
github.com/hatchet-dev/hatchet
golang/github.com/hatchet-dev/hatchet
Go
< 0.95.3
0.95.3

References

GitHub Advisory / Wiki ADVISORY
https://github.com/hatchet-dev/hatchet/security/advisories/GHSA-9q4h-f4x5-ffq8
NVD — CVE-2026-84298 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-84298
Security Fix Commit FIX COMMIT
https://github.com/hatchet-dev/hatchet/commit/9555bfdd1e97f61d25e614ccaa107c5fb7dc4976
Hatchet Source Repository REPOSITORY
https://github.com/hatchet-dev/hatchet

Frequently Asked Questions

What is CVE-2026-84298?
CVE-2026-84298 is a security vulnerability in Hatchet involving Cross-tenant durable callback payload disclosure in Hatchet V1 Dispatcher under CWE-639: Authorization Bypass Through User-Controlled Key.
Which Hatchet versions are affected?
Affected versions include releases prior to 0.95.3 across affected packages: github.com/hatchet-dev/hatchet.
What version fixes CVE-2026-84298?
Upgrading to 0.95.3 (or the latest patched release for your respective branch) resolves the vulnerability.
Is github.com/hatchet-dev/hatchet affected?
Yes, github.com/hatchet-dev/hatchet is affected in releases prior to 0.95.3. Upgrade your dependency to 0.95.3 or later.
What is the CVSS score of CVE-2026-84298?
CVE-2026-84298 has a CVSS v3.1 base score of 3.1 (LOW) with vector string CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N.
What CWE is associated with CVE-2026-84298?
CVE-2026-84298 is classified under CWE-639: Authorization Bypass Through User-Controlled Key (The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.).
How can I check Go dependencies for CVE-2026-84298?
Run the dependency tree command: 'inspect dependencies for github.com/hatchet-dev/hatchet'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-9q4h-f4x5-ffq8",
  "modified" : "2026-09-22T20:40:43Z",
  "published" : "2026-09-22T20:40:43Z",
  "aliases" : [ "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).",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:N/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/hatchet-dev/hatchet"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.95.3"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "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" : "WEB",
    "url" : "https://github.com/hatchet-dev/hatchet/commit/9555bfdd1e97f61d25e614ccaa107c5fb7dc4976"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/hatchet-dev/hatchet"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-639", "CWE-862" ],
    "severity" : "LOW",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-09-22T20:40:43Z",
    "nvd_published_at" : "2026-09-21T16:17:24Z"
  }
}