Apache Zookeeper

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.

Published: 2026-03-07T08:51:17.567Z
Updated: 2026-07-15T02:46:52.345Z

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.

Published: 2026-03-07T08:50:32.525Z
Updated: 2026-07-15T01:17:24.357Z

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.)

Published: 2025-09-24T09:29:35.824Z
Updated: 2025-11-04T21:13:42.037Z

When using IPAuthenticationProvider in ZooKeeper Admin Server there is a possibility of Authentication Bypass by Spoofing -- this only impacts IP based authentication implemented in ZooKeeper Admin Server. Default configuration of client's IP address detection in IPAuthenticationProvider, which uses HTTP request headers, is weak and allows an attacker to bypass authentication via spoofing client's IP address in request headers. Default configuration honors X-Forwarded-For HTTP header to read client's IP address. X-Forwarded-For request header is mainly used by proxy servers to identify the client and can be easily spoofed by an attacker pretending that the request comes from a different IP address. Admin Server commands, such as snapshot and restore arbitrarily can be executed on successful exploitation which could potentially lead to information leakage or service availability issues. Users are recommended to upgrade to version 3.9.3, which fixes this issue.

Published: 2024-11-07T09:52:03.957Z
Updated: 2024-11-07T16:33:08.247Z

Information disclosure in persistent watchers handling in Apache ZooKeeper due to missing ACL check. It allows an attacker to monitor child znodes by attaching a persistent watcher (addWatch command) to a parent which the attacker has already access to. ZooKeeper server doesn't do ACL check when the persistent watcher is triggered and as a consequence, the full path of znodes that a watch event gets triggered upon is exposed to the owner of the watcher. It's important to note that only the path is exposed by this vulnerability, not the data of znode, but since znode path can contain sensitive information like user name or login ID, this issue is potentially critical. Users are recommended to upgrade to version 3.9.2, 3.8.4 which fixes the issue.

Published: 2024-03-15T10:26:12.848Z
Updated: 2025-07-03T14:52:57.231Z