hatchet - Unauthenticated OAuth state CSRF / login-CSRF via empty-state collision in ValidateOAuthState

published 2026-09-21 48 d ago modified 2026-11-04 4 d ago also GHSA-phg3-3g28-wq9v , GO-2026-6535 , EUVD-2026-83978

cvss: 7.1; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 6%
public exploits: 0; none known

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.

Patch / fix

fixed in 1 links 1

go github.com/hatchet-dev/hatchet 0.91.1, 0.91.2

github.com/hatchet-dev/hatchet@f904641 commit

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 48 d ago (2026-09-21)

Exploit prediction

0.17% chance of exploitation in the next 30 days, higher than 6% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	7.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:N
GitHub	3.1	7.1	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:H/A:N

Affected packages

ecosystem	package	affected	fixed in
go	github.com/hatchet-dev/hatchet	<0.91.1 <0.91.2	0.91.1 0.91.2

Affected products

hatchet-dev hatchet

Classification

Weakness

CWE-287 Improper Authentication
CWE-352 Cross-Site Request Forgery
CWE-384 Session Fixation
CWE-1275 Sensitive Cookie with Improper SameSite Attribute

References

github.com /hatchet-dev/hatchet/commit/f90464189ad642251e09412d0f99fde353036428
web, patch
github.com /hatchet-dev/hatchet/security/advisories/GHSA-phg3-3g28-wq9v
web, advisory
nvd.nist.gov /vuln/detail/CVE-2026-61687
advisory
github.com /hatchet-dev/hatchet
package

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary