CVE-2026-61709
mediumpriority · track · 0OT risk · elevatedEPSS 0.004 · 29 %ileUSEPSS · scored 2026-10-28
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 relation used an intersection containing a base but not excluded operand, the base was granted through a type-bound public wildcard, and the excluded user also had a concrete tuple through another intersection operand. In pkg/server/commands/listusers/list_users_rpc.go, expandIntersection counted the concrete tuple and wildcard without first rejecting entries in excludedUsersMap. Applications that used ListUsers to enumerate or enforce access could therefore treat an excluded user as authorized. This issue is fixed in version 1.18.1.
cvss
Technical severity, 0–10. One row per scoring source.
base score 0–10 · higher = more severe · hover a vector to decode
ssvc
A stakeholder decision — act, attend, or track — from exploitation and impact.
weaknesses
The CWE weakness classes this flaw belongs to.
affected products (1)
Products and version ranges known to be affected.
advisories (2)
Vendor and ecosystem advisories describing this.
- GHSA-g3pg-frfm-pr2mOpenFGA: 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 user2026-09-16ghsa · osvUS
### 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.
- GO-2026-6488OpenFGA: 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 in github.com/openfga/openfga2026-09-28vendor · osvUS
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 in github.com/openfga/openfga
also known as (2)
Other names and identifiers for this entity.
- GHSA-g3pg-frfm-pr2mosv
- GO-2026-6488osv
sources
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references (3) nvd
External citations — patches, advisories, analysis.
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