Apache: >> Zookeeper >> 3.9.3 Security Vulnerabilities
Hostname verification in Apache ZooKeeper ZKTrustManager falls back to reverse DNS (PTR) when IP SAN validation fails, allowing attackers who control or spoof PTR records to impersonate ZooKeeper servers or clients with a valid certificate for the PTR name. It's important to note that attacker must present a certificate which is trusted by ZKTrustManager which makes the attack vector harder to exploit. Users are recommended to upgrade to version 3.8.6 or 3.9.5, which fixes this issue by introducing a new configuration option to disable reverse DNS lookup in client and quorum protocols.
CVSS Score
7.4
EPSS Score
0.0
Published
2026-03-07
Improper handling of configuration values in ZKConfig in Apache ZooKeeper 3.8.5 and 3.9.4 on all platforms allows an attacker to expose sensitive information stored in client configuration in the client's logfile. Configuration values are exposed at INFO level logging rendering potential production systems affected by the issue. Users are recommended to upgrade to version 3.8.6 or 3.9.5 which fixes this issue.
CVSS Score
7.5
EPSS Score
0.0
Published
2026-03-07
Improper permission check in ZooKeeper AdminServer lets authorized clients to run snapshot and restore command with insufficient permissions.
This issue affects Apache ZooKeeper: from 3.9.0 before 3.9.4.
Users are recommended to upgrade to version 3.9.4, which fixes the issue.
The issue can be mitigated by disabling both commands (via admin.snapshot.enabled and admin.restore.enabled), disabling the whole AdminServer interface (via admin.enableServer), or ensuring that the root ACL does not provide open permissions. (Note that ZooKeeper ACLs are not recursive, so this does not impact operations on child nodes besides notifications from recursive watches.)
CVSS Score
4.3
EPSS Score
0.001
Published
2025-09-24