Executive brief
Kibana's Agent Builder feature determines private agent ownership by username, but usernames are not unique across different Elasticsearch authentication realms. This flaw allows an attacker with login credentials (even in a different realm) to view, modify, or delete private agents belonging to another user who shares the same username in a different realm. Organizations using multiple authentication methods could see sensitive agent configurations exposed or altered by unauthorized users.
Technical details
The vulnerability is an incorrect authorization flaw (CWE-863) in Kibana's Agent Builder. The component determines ownership of private agents by comparing a stable user identifier when available, but falls back to username comparison when the identifier is not recorded. Since usernames are not unique across Elasticsearch authentication realms, two distinct principals sharing a username in different realms are treated as the same owner. An authenticated attacker (PR:L) can exploit this over the network (AV:N) to disclose configuration and instructions of agents they do not own, and to alter or remove them. The issue affects Kibana versions 9.4.0 through 9.4.4 and 9.5.0, and is resolved in versions 9.4.5 and 9.5.1. No workarounds are available for unpatched systems.
Affected products
- Elastic Kibana 9.4.0 through 9.4.4, 9.5.0
Timeline
- 2026-08-13: disclosed
- 2026-08-13: patched: Fixed in Kibana 9.4.5 and 9.5.1