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Vulnerability record · CVE-2026-24281 · published 7 March 2026

CVE-2026-24281: Apache zookeeper improper certificate validation vulnerability

Apache · Zookeeper

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.

7.4 CVSS 3.1 High EPSS 0.63% · top 51.7% CWE-295 · Improper certificate validationCWE-350 · CWE-350
7.4CVSS 3.1 base score
0.63%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
10References
15 Jul 2026Last modified by NVD

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/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://lists.apache.org/thread/088ddsbrzhd5lxzbqf5n24yg0mwh9jt2 Mailing ListVendor Advisory
http://www.openwall.com/lists/oss-security/2026/03/07/4 Mailing ListThird 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

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Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-24281), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.