Apache · Apache Zookeeper · CVE-2023-44981
**Name of the Vulnerable Software and Affected Versions**
Apache ZooKeeper versions prior to 3.7.2
Apache ZooKeeper versions prior to 3.8.3
Apache ZooKeeper versions prior to 3.9.1
**Description**
The issue is related to an Authorization Bypass Through User-Controlled Key vulnerability in Apache ZooKeeper. If SASL Quorum Peer authentication is enabled, the authorization check can be skipped if the instance part in the SASL authentication ID is missing. This allows an arbitrary endpoint to join the cluster and propagate counterfeit changes to the leader, giving it complete read-write access to the data tree. Quorum Peer authentication is not enabled by default.
**Recommendations**
To resolve the issue, upgrade to version 3.7.2, 3.8.3, or 3.9.1, which fixes the issue.
Alternatively, ensure the ensemble election/quorum communication is protected by a firewall to mitigate the issue.