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.
Attack Parameters
Attack Vector
Network
Can be exploited remotely
Attack Complexity
High
Difficult to exploit
Privileges Required
Low
Basic privileges needed
User Interaction
None
No user interaction needed
Impact Assessment
Confidentiality
High
Complete data leak
Integrity
None
No data modification
Availability
None
No disruption
CVSS Vector v3.1
Weakness Type (CWE)
References 3
https://github.com/openfga/openfga/commit/171806c93b86bca29e0212ceb8b6ee9c48eb9…
security-advisories@github.com
https://github.com/openfga/openfga/releases/tag/v1.18.1
security-advisories@github.com
https://github.com/openfga/openfga/security/advisories/GHSA-g3pg-frfm-pr2m
security-advisories@github.com