Bug 2535473 (CVE-2026-61709)

Summary: CVE-2026-61709 github.com/openfga/openfga: OpenFGA: Unauthorized access due to ListUsers API returning deliberately excluded users.
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedCC: amctagga, aoconnor, bniver, flucifre, gmeno, gparvin, groman, jbalunas, lchilton, mbenjamin, mhackett, rhaigner, rhel-process-autobot, sfeifer, sostapov, tsze, vereddy, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in OpenFGA, an authorization and permission engine. The ListUsers application programming interface (API) could incorrectly return users who should have been excluded from authorization decisions. This vulnerability arises when complex authorization rules, involving both exclusions and type-bound wildcards, are processed. Consequently, applications relying on ListUsers for access control might inadvertently grant unauthorized access to resources or sensitive information.
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Description OSIDB Bzimport 2026-09-16 14:34:24 UTC 
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.