GHSA-7xrh-hqfc-g7qr
Apache ZooKeeper: Reverse-DNS fallback enables hostname verification bypass in ZooKeeper ZKTrustManager
Quick fix
GHSA-7xrh-hqfc-g7qr — org.apache.zookeeper:zookeeper: upgrade to the fixed version with the command below.
# pom.xml: bump <version>3.8.6</version> for org.apache.zookeeper:zookeeperDetails
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.
Are you affected?
Enter the version of the package you're using.
Affected packages
3.8.0Fixed in: 3.8.6# pom.xml: bump <version>3.8.6</version> for org.apache.zookeeper:zookeeper3.9.0Fixed in: 3.9.5# pom.xml: bump <version>3.9.5</version> for org.apache.zookeeper:zookeeperReferences
- https://nvd.nist.gov/vuln/detail/CVE-2026-24281[ADVISORY]
- https://github.com/apache/zookeeper/commit/66c4efecdda1302d9cfb3af9eedb122b74452bf3[WEB]
- https://github.com/apache/zookeeper[PACKAGE]
- https://issues.apache.org/jira/browse/ZOOKEEPER-4986[WEB]
- https://lists.apache.org/thread/088ddsbrzhd5lxzbqf5n24yg0mwh9jt2[WEB]
- http://www.openwall.com/lists/oss-security/2026/03/07/4[WEB]