{"id":"CVE-2026-61687","kind":"vulnerability","aliases":["CVE-2026-61687","GHSA-phg3-3g28-wq9v","GO-2026-6535"],"related":[],"title":"Unauthenticated OAuth state CSRF via empty-state collision in ValidateOAuthState in github.com/hatchet-dev/hatchet","description":"Hatchet is a platform for orchestrating background tasks, AI agents, and durable workflows at scale. Prior to 0.91.1, ValidateOAuthState clears the oauth_state_ session value to an empty string after a successful OAuth callback and later accepts an empty state parameter as equal, allowing an unauthenticated attacker to bind a victim's Hatchet session to an attacker-controlled OAuth identity. Exploitation requires the victim to have completed an OAuth flow in the current session and the deployment to enable auth.google.enabled, auth.github.enabled, or the Slack integration. This issue is fixed in version 0.91.1.","summary":"Hatchet's ValidateOAuthState clears the oauth_state_ session value to an empty string after a successful OAuth callback, then accepts an empty state parameter as a match. An unauthenticated attacker can bind a victim's Hatchet session to an attacker-controlled OAuth identity.","severity":"high","cvss":7.1,"epss":0.00171,"exploited":false,"exploited_at":null,"products":[{"name":"github.com/hatchet-dev/hatchet","fixed":["0.91.2"],"affected":"< 0.91.2","ecosystem":"go"}],"ecosystems":["go"],"tags":["github-oauth","google-oauth","hatchet","runtime","self-hosted","slack"],"not_affected_if":["default-config","oauth-disabled"],"how_to_check":"Check whether the deployed Hatchet version is below 0.91.2 (go.mod: github.com/hatchet-dev/hatchet).\nConfirm whether auth.google.enabled, auth.github.enabled, or the Slack integration is turned on.","fix":"Upgrade github.com/hatchet-dev/hatchet to 0.91.2 (the sources conflict: the description says 0.91.1).","status":"open","published_at":"2026-09-21T16:17:09+00:00","first_seen_at":"2026-10-23T19:13:08+00:00","triaged_at":"2026-10-23T21:45:51+00:00","updated_at":"2026-10-23T21:45:51+00:00","category":"runtime","confidence":0.6,"triage":{"at":"2026-10-23T21:45:51Z","model":"claude-haiku-5-5","output":{"fix":"Upgrade github.com/hatchet-dev/hatchet to 0.91.2 (the sources conflict: the description says 0.91.1).","reach":"internet","impact":"medium","summary":"Hatchet's ValidateOAuthState clears the oauth_state_ session value to an empty string after a successful OAuth callback, then accepts an empty state parameter as a match. An unauthenticated attacker can bind a victim's Hatchet session to an attacker-controlled OAuth identity.","category":"runtime","who_cares":["hatchet","self-hosted","google-oauth","github-oauth","slack"],"confidence":0.6,"needs_auth":"no","worst_case":"Victim's Hatchet session is bound to an attacker's OAuth identity","analyst_note":"Sources conflict on the fixed version (0.91.1 in the description, 0.91.2 in the affected range); verify at https://pkg.go.dev/vuln/GO-2026-6535 and the NVD entry.","how_to_check":"Check whether the deployed Hatchet version is below 0.91.2 (go.mod: github.com/hatchet-dev/hatchet).\nConfirm whether auth.google.enabled, auth.github.enabled, or the Slack integration is turned on.","needs_analyst":true,"not_affected_if":["oauth-disabled","default-config"],"user_interaction":"unknown","needs_special_setup":"yes","severity_if_unknown":"unknown"},"cost_usd":0.00101,"input_tokens":3049,"output_tokens":1410,"severity_before":"high"},"analyst_status":null,"analyst_note":null,"search":"'-2026':17A,25A,28A '-61687':18A,29A '-6535':26A '/hatchet-dev/hatchet':15A,32A '0.91.1':106C,181C '3g28':22A 'accept':64B,125C 'agent':98C 'ai':97C 'allow':132C 'attack':74B,85B,135C,146C 'attacker-control':84B,145C 'auth.github.enabled':170C 'auth.google.enabled':169C 'background':95C 'bind':76B,137C 'callback':62B,122C 'clear':48B,108C 'collis':9A 'complet':156C 'control':86B,147C 'csrf':4A 'current':162C 'cve':16A,27A 'deploy':166C 'durabl':100C 'empti':7A,56B,66B,116C,127C 'empty-st':6A 'enabl':168C 'equal':131C 'exploit':150C 'fix':178C 'flow':159C 'ghsa':20A 'ghsa-phg3-3g28-wq9v':19A 'github':34B 'github-oauth':33B 'github.com':14A,31A 'github.com/hatchet-dev/hatchet':13A,30A 'go':24A 'googl':37B 'google-oauth':36B 'hatchet':39B,45B,80B,89C,141C 'host':43B 'ident':88B,149C 'integr':174C 'issu':176C 'later':124C 'match':71B 'oauth':2A,35B,38B,50B,61B,87B,110C,121C,148C,158C 'orchestr':94C 'paramet':68B,129C 'phg3':21A 'platform':92C 'prior':104C 'requir':151C 'runtim':40B 'scale':103C 'self':42B 'self-host':41B 'session':52B,81B,112C,142C,163C 'slack':44B,173C 'state':3A,8A,51B,67B,111C,128C 'string':57B,117C 'success':60B,120C 'task':96C 'unauthent':1A,73B,134C 'validateoauthst':11A,47B,107C 'valu':53B,113C 'version':180C 'via':5A 'victim':78B,139C,153C 'workflow':101C 'wq9v':23A","nicknames":[],"mitigations":[],"who_affected":null,"tier":null,"verified":{},"analyst_revisit_at":null,"first_public_at":"2026-09-21T16:17:09+00:00","kev":null,"cvss_vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:N","cvss_by":"security-advisories@github.com","poc_count":0,"sources":[{"source":"govuln","external_id":"GO-2026-6535","url":"https://pkg.go.dev/vuln/GO-2026-6535","severity":null,"published_at":"2026-09-28T16:43:40+00:00","modified_at":"2026-10-07T14:10:24+00:00","first_seen_at":"2026-10-23T19:13:08+00:00","fetched_at":"2026-10-23T19:13:08+00:00","note":null},{"source":"epss","external_id":"CVE-2026-61687","url":"https://api.first.org/data/v1/epss?cve=CVE-2026-61687","severity":null,"published_at":null,"modified_at":null,"first_seen_at":"2026-10-23T19:13:43+00:00","fetched_at":"2026-10-23T19:13:43+00:00","note":null},{"source":"nvd","external_id":"CVE-2026-61687","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-61687","severity":null,"published_at":"2026-09-21T16:17:09+00:00","modified_at":"2026-09-24T21:25:27+00:00","first_seen_at":"2026-10-23T19:35:23+00:00","fetched_at":"2026-10-23T19:35:23+00:00","note":null}],"documents":[],"notice":"Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai"}