CVE-2026-91644: Critical access-control vulnerability in Oracle Essbase

A vulnerability in the security component of Oracle Essbase affects supported version 21.8.3.0.0. An unauthenticated attacker with network access can easily exploit it via HTTP. Successful exploitation may provide unauthorized access to critical data or complete access to all data accessible through Oracle Essbase, as well as unauthorized update, insertion, or deletion access to some accessible data.