← CVE Intelligence

CVE-2026-24281

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

Description (CNA)

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 (CNA)

Vendor / productVersions
Apache Software Foundation / Apache ZooKeeperaffected 3.9.0 through 3.9.4; affected 3.8.0 through 3.8.5

CWE

CWE-350, CWE-295

References

ADP enrichment

CVE

No English description supplied.

CISA-ADP

No English description supplied.

No references supplied.

redhat-SADP

A flaw was found in Apache ZooKeeper. The ZKTrustManager component's hostname verification process can fall back to reverse DNS (PTR) lookup when IP Subject Alternative Name (SAN) validation fails. This vulnerability allows an attacker who can control or spoof PTR records to impersonate ZooKeeper servers or clients, provided they possess a valid certificate for the PTR name. This could lead to unauthorized access or manipulation of ZooKeeper services.