OpenFGA: ListUsers returns a deliberately-excluded user when a `but not` exclusion under a type-bound wildcard is intersected (`and`) with another relation that also grants that user
### Description In OpenFGA, the ListUsers API could incorrectly return a user who should have been excluded. ### Preconditions This applies if all of the following are present: - The authorization model contains a relation defined as an intersection (and) where at least one operand is an exclusion of the form base but not excluded: e.g. `rel1: (public_user but not blocked) and rel2` - The base side of that exclusion is granted through a type-bound public wildcard (e.g. user:*). - A user excluded by the but not clause is also granted, via a concrete tuple, through another operand of the intersection. - Your application uses ListUsers to enumerate or enforce access ### Fix Upgrade to OpenFGA v1.18.1 or greater. ### Acknowledgements OpenFGA would like to thank @5ud0er for the detailed report.
describes (1)
Related CVEs.
| ID | severity | exploitable | ||
|---|---|---|---|---|
| CVE-2026-61709US | —OT elevated | — | ||
OpenFGA is an authorization and permission engine built for developers. Prior to 1.18.1, the ListUsers API could return a user that should have been excluded when an authorization… | ||||
references
External citations — patches, advisories, analysis.
- https://github.com/openfga/openfgaPACKAGE
- https://github.com/openfga/openfga/commit/171806c93b86bca29e0212ceb8b6ee9c48eb9ac3WEB
- https://github.com/openfga/openfga/releases/tag/v1.18.1WEB
- https://github.com/openfga/openfga/security/advisories/GHSA-g3pg-frfm-pr2mWEB
- https://nvd.nist.gov/vuln/detail/CVE-2026-61709ADVISORY
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