Kibana Agent Builder: multiple authorization and denial-of-service flaws in RAG/agent features

Elastic disclosed a cluster of Kibana Agent Builder CVEs on 2026-08-13: CVE-2026-72643 (CVSS 7.1, High) — private-agent ownership check falls back to non-unique username comparison across realms, allowing cross-user access; CVE-2026-72680 (CVSS 6.5, Medium) — A2A JSON-RPC endpoint does not distinguish a non-existent conversation from one owned by another user, an IDOR; CVE-2026-72681 (CVSS 6.5, Medium) — Agent Builder fails to verify a user holds required privileges before creating/running a tool that invokes another Kibana feature's functionality, enabling privilege escalation; CVE-2026-72674 (CVSS 6.5, Medium) — unbounded document-field list in Kibana Playground for RAG causes denial of service.

Kibana Agent Builder is Elastic's agentic/RAG feature layered on top of its widely-deployed observability platform; these flaws collectively allow cross-user data access, privilege escalation into unrelated Kibana features via agent tool creation, and DoS against the RAG playground — a meaningful blast radius given Kibana's broad enterprise deployment footprint.

Authenticated Kibana users exploit username-comparison fallback, IDOR on conversation identifiers, or missing privilege checks on agent tool creation to access other users' agents/conversations or escalate privileges; unauthenticated field-list flooding causes RAG playground DoS

Kibana Agent Builder (versions per individual advisory, generally 8.19.20/9.4.5/9.5.1 fix lines)

Upgrade to Kibana 8.19.20, 9.4.5, or 9.5.1 per the specific ESA advisory