CVE-2026-24281
Apache ZooKeeper: Reverse-DNS fallback enables hostname verification bypass in ZooKeeper ZKTrustManager
MEDIUM 5.9
At a glance
- Source
- NVD
- EPSS
- EPSS 0.65 % · percentile 51 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- apache
- NVD status
- Modified
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.
Weaknesses (CWE)
References
- https://lists.apache.org/thread/088ddsbrzhd5lxzbqf5n24yg0mwh9jt2
- http://www.openwall.com/lists/oss-security/2026/03/07/4
- 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
- https://access.redhat.com/errata/RHSA-2026:14276
- https://access.redhat.com/errata/RHSA-2026:14272
- https://access.redhat.com/errata/RHSA-2026:8509
- https://access.redhat.com/errata/RHSA-2026:10184
- https://access.redhat.com/errata/RHSA-2026:34608
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | MEDIUM 5.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N | CISA-ADP |
| CVSS 3.1 | HIGH 7.4 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N | redhat-SADP |
| CVSS 3.1 | HIGH 7.4 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N | NVD · nvd@nist.gov (Primary) |
| CVSS 3.1 | MEDIUM 5.9 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N | NVD · 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary) |
| CVSS 3.1 | HIGH 7.4 | CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N | NVD · 0b0ca135-0b70-47e7-9f44-1890c2a1c46c (Secondary) |
Advisories
- GHSA-7xrh-hqfc-g7qr — Apache ZooKeeper: Reverse-DNS fallback enables hostname verification bypass in ZooKeeper ZKTrustManager
European references
- ENISA EUVD · EUVD-2026-10139
- GCVE · GCVE-0-2026-24281
CERT-FR advisories
- CERTFR-2026-AVI-1336 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0933 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0641 — Multiples vulnérabilités dans les produits IBM · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0556 — Multiples vulnérabilités dans les produits VMware · cert.ssi.gouv.fr
- CERTFR-2026-AVI-0251 — Multiples vulnérabilités dans Apache Zookeeper · cert.ssi.gouv.fr
Affected configurations (NVD CPE)
cpe:2.3:a:apache:zookeeper:*:*:*:*:*:*:*:*≥ 3.8.0 < 3.8.6cpe:2.3:a:apache:zookeeper:*:*:*:*:*:*:*:*≥ 3.9.0 < 3.9.5
Affected products
| Product | Versions |
|---|---|
| Apache Software Foundation · Apache ZooKeeper | affected 3.9.0 ≤ 3.9.4 ; affected 3.8.0 ≤ 3.8.5 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| CERT-FR (ANSSI) | Licence Ouverte / Etalab 2.0 |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |