CVE-2026-24281
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…
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.63%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
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.
- CVSS 3.1
- 7.4 HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
- EPSS
- 0.63% probability · 48th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-295, CWE-350
- Affected
- apache/zookeeper
- Source
- security@apache.org
References
- https://lists.apache.org/thread/088ddsbrzhd5lxzbqf5n24yg0mwh9jt2Mailing List, Vendor Advisory
- http://www.openwall.com/lists/oss-security/2026/03/07/4Mailing List, Third Party Advisory
- https://access.redhat.com/errata/RHSA-2026:10184
- https://access.redhat.com/errata/RHSA-2026:14272
- https://access.redhat.com/errata/RHSA-2026:14276
- https://access.redhat.com/errata/RHSA-2026:34608
- https://access.redhat.com/errata/RHSA-2026:8509
- https://access.redhat.com/security/cve/CVE-2026-24281
- https://bugzilla.redhat.com/show_bug.cgi?id=2445449
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-24281.json
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.