CVE-2026-61687: Hatchet Hatchet - Unauthenticated OAuth State Vulnerability

HIGH
Advisory Identifier: GHSA-phg3-3g28-wq9v
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CVSS 7.1
CWE-384 CWE-287 CWE-1275 CWE-352
Published
Advisory Summary

CVE-2026-61687 is a HIGH (CVSS 7.1) hatchet - unauthenticated oauth state vulnerability (CWE-384: Session Fixation) affecting Hatchet libraries in the Go ecosystem. The issue involves hatchet - unauthenticated oauth state csrf / login-csrf via empty-state collision in validateoauthstate. Remediation is available by upgrading affected packages to version 0.91.1.

CVE-2026-61687 at a Glance

CVE Identifier CVE-2026-61687
GHSA Identifier GHSA-phg3-3g28-wq9v
Severity HIGH
CVSS v3.1 Base Score 7.1
CWE Classification CWE-384: Session Fixation
Affected Product Hatchet
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 7.1

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

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

How to Fix CVE-2026-61687

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.

hatchet fixed: 0.91.1 
Upgrade hatchet to 0.91.1
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 hatchet

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-61687, inspect your project dependencies for Hatchet:

inspect dependencies for 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 0.91.1), 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-384: Session Fixation, where authenticating a user, or otherwise establishing a new user session, without invalidating any existing session identifier gives an attacker the opportunity to steal authenticated sessions. 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 Hatchet version v0.86.26 and below is vulnerable to OAuth state CSRF (login CSRF / account fixation). The vulnerable code clears the session `oauth_state_<integration>` value to the empty string `""` after a successful OAuth callback rather than removing the key, and the subsequent state-equality check then accepts an empty `?state=` parameter on any later callback request — allowing an unauthenticated attacker to bind an already-authenticated victim's session cookie to an attacker-controlled OAuth identity (account takeover via login-CSRF). ### Impact Affected configurations: any deployment that has enabled at least one of `auth.google.enabled`, `auth.github.enabled`, or the Slack integration, and where the victim has completed at least one OAuth flow on that integration in the current session. Bug present on `main` HEAD and in every tagged release up to and including v0.86.26 (commit `243f41d9e1161e70d47dfc0a6509f1c4ddfc9c23`).

CVE-2026-61687 Affected Hatchet Versions

1 component(s)
Fixed Versions:
0.91.1
Product / Package Ecosystem Affected Versions Fixed Version
hatchet
golang/hatchet
Go
< 0.91.1
0.91.1

References

GitHub Advisory / Wiki ADVISORY
https://github.com/hatchet-dev/hatchet/security/advisories/GHSA-phg3-3g28-wq9v
Security Fix Commit FIX COMMIT
https://github.com/hatchet-dev/hatchet/commit/f90464189ad642251e09412d0f99fde353036428
Hatchet Source Repository REPOSITORY
https://github.com/hatchet-dev/hatchet

Frequently Asked Questions

What is CVE-2026-61687?
CVE-2026-61687 is a security vulnerability in Hatchet involving Hatchet - Unauthenticated OAuth state CSRF / login-CSRF via empty-state collision in ValidateOAuthState under CWE-384: Session Fixation.
Which Hatchet versions are affected?
Affected versions include releases prior to 0.91.1 across affected packages: hatchet.
What version fixes CVE-2026-61687?
Upgrading to 0.91.1 (or the latest patched release for your respective branch) resolves the vulnerability.
Is hatchet affected?
Yes, hatchet is affected in releases prior to 0.91.1. Upgrade your dependency to 0.91.1 or later.
What is the CVSS score of CVE-2026-61687?
CVE-2026-61687 has a CVSS v3.1 base score of 7.1 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:N.
What CWE is associated with CVE-2026-61687?
CVE-2026-61687 is classified under CWE-384: Session Fixation (Authenticating a user, or otherwise establishing a new user session, without invalidating any existing session identifier gives an attacker the opportunity to steal authenticated sessions.).
How can I check Go dependencies for CVE-2026-61687?
Run the dependency tree command: 'inspect dependencies for 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-phg3-3g28-wq9v",
  "modified" : "2026-09-21T15:47:01Z",
  "published" : "2026-09-21T15:47:01Z",
  "aliases" : [ "CVE-2026-61687" ],
  "summary" : "Hatchet - Unauthenticated OAuth state CSRF / login-CSRF via empty-state collision in ValidateOAuthState",
  "details" : "### Summary\n\nHatchet version v0.86.26 and below is vulnerable to OAuth state CSRF (login CSRF / account fixation). \n\nThe vulnerable code clears the session `oauth_state_<integration>` value to the empty string `\"\"` after a successful OAuth callback rather than removing the key, and the subsequent state-equality check then accepts an empty `?state=` parameter on any later callback request — allowing an unauthenticated attacker to bind an already-authenticated victim's session cookie to an attacker-controlled OAuth identity (account takeover via login-CSRF). \n\n\n### Impact\n\nAffected configurations: any deployment that has enabled at least one of `auth.google.enabled`, `auth.github.enabled`, or the Slack integration, and where the victim has completed at least one OAuth flow on that integration in the current session. Bug present on `main` HEAD and in every tagged release up to and including v0.86.26 (commit `243f41d9e1161e70d47dfc0a6509f1c4ddfc9c23`).",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "hatchet"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "0.91.1"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/hatchet-dev/hatchet/security/advisories/GHSA-phg3-3g28-wq9v"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/hatchet-dev/hatchet/commit/f90464189ad642251e09412d0f99fde353036428"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/hatchet-dev/hatchet"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-1275", "CWE-287", "CWE-352", "CWE-384" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-09-21T15:47:01Z",
    "nvd_published_at" : null
  }
}