CVE-2026-61709 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
Attackers can bypass authorization checks in OpenFGA's ListUsers API when specific intersection and exclusion logic is used, gaining unauthorized access.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-61709?
CVE-2026-61709 is a medium-severity missing authorization vulnerability in openfga, published on 16 Sep 2026. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
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.
Which versions are affected by CVE-2026-61709?
3 open source packages ship an affected version, including github.com/openfga/openfga.
| Package | Affected | Fixed in |
|---|---|---|
github.com/openfga/openfga Go | All versions | 1.18.1 |
github.com/openfga/openfga Go | All versions | 1.18.1 |
github.com/openfga/openfga Go | All versions | 1.18.1 |
How do I fix CVE-2026-61709?
Upgrade github.com/openfga/openfga to 1.18.1 or later.
Upgrade, and check permissions on every request on the server, not only in the interface. More about Missing authorization.
Is CVE-2026-61709 being exploited?
There is no known exploitation of CVE-2026-61709 in the wild and no public exploit code.
Sources
Also known as CLEANSTART-2026-LI79671, ECHO-cd63-9789-8fd2, GHSA-g3pg-frfm-pr2m, GO-2026-6488, MINI-2m3c-29mw-r27x, MINI-2p49-w43h-pgh3 and 20 more.