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CVE PROGRAM SOURCE RECORD5.9 Medium

CVE-2026-24281

Apache ZooKeeper: Reverse-DNS fallback enables hostname verification bypass in ZooKeeper ZKTrustManager

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Status
Published
Published
Updated
Assigning organization
apache

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.

Affected products

Version statuses are supplied by the assigning organization. Consult the original record for detailed ranges and platform conditions.

Apache Software Foundation Apache ZooKeeper

Default version status: unaffected

  • 3.9.0 to ≤ 3.9.4affected
  • 3.8.0 to ≤ 3.8.5affected

References