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.
History

Mon, 09 Mar 2026 10:15:00 +0000

Type Values Removed Values Added
First Time appeared Apache
Apache zookeeper
Vendors & Products Apache
Apache zookeeper

Sat, 07 Mar 2026 17:30:00 +0000

Type Values Removed Values Added
References

Sat, 07 Mar 2026 09:00:00 +0000

Type Values Removed Values Added
Description 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.
Title Apache ZooKeeper: Reverse-DNS fallback enables hostname verification bypass in ZooKeeper ZKTrustManager
Weaknesses CWE-295
CWE-350
References

cve-icon MITRE

Status: PUBLISHED

Assigner: apache

Published: 2026-03-07T08:50:32.525Z

Updated: 2026-03-07T17:05:10.486Z

Reserved: 2026-01-21T19:40:25.776Z

Link: CVE-2026-24281

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-03-07T09:16:07.437

Modified: 2026-03-09T13:35:34.633

Link: CVE-2026-24281

cve-icon Redhat

No data.