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
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| Apache Software Foundation | Apache ZooKeeper | 3.9.0 – ≤ 3.9.4, 3.8.0 – ≤ 3.8.5 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | zookeeper | 3.9.5-1 | — |
| Debian 13 | zookeeper | No fix yet | — |
| Debian 12 | zookeeper | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | zookeeper | No fix yet | — |
| Ubuntu 26.04 LTS | zookeeper | No fix yet | — |
| Ubuntu 25.10 | zookeeper | No fix yet | — |
| Ubuntu 24.04 LTS | zookeeper | No fix yet | — |
| Ubuntu 22.04 LTS | zookeeper | No fix yet | — |
Show 4 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 20.04 LTS | zookeeper | No fix yet | — |
| Ubuntu Pro 18.04 LTS | zookeeper | No fix yet | — |
| Ubuntu Pro 16.04 LTS | zookeeper | No fix yet | — |
| Ubuntu Pro 14.04 LTS | zookeeper | No fix yet | — |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | akhq | 0.26.0-r11 | — |
| Wolfi rolling | apache-activemq-artemis | 2.53.0-r2 | — |
| Wolfi rolling | apache-nifi | 2.8.0-r4 | — |
| Wolfi rolling | confluent-common-docker | No fix yet | — |
| Wolfi rolling | kserve-modelmesh | 0.12.0-r26 | — |
| Wolfi rolling | spark-4.0-scala-2.13 | 4.0.2-r7 | — |
| Wolfi rolling | spark-4.1-scala-2.13 | 4.1.1-r7 | — |
| Wolfi rolling | strimzi-kafka-operator-kafka-thirdparty-libs-cc | 0.51.0-r1 | — |
| Wolfi rolling | trino-plugin-kafka +3 | 480-r0 | — |
| Wolfi rolling | zookeeper-3.9 | 3.9.5-r0 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Maven | org.apache.zookeeper:zookeeper | >= 3.8.0, < 3.8.6 | 3.8.6 | GHSA-7xrh-hqfc-g7qr |
| Maven | org.apache.zookeeper:zookeeper | >= 3.9.0, < 3.9.5 | 3.9.5 | GHSA-7xrh-hqfc-g7qr |
Advisories 1
- WID-SEC-2026-1032 IBM Tivoli Network Manager: Mehrere Schwachstellen BSI CERT-Bund (WID) · Jun 7, 2026
References
- https://lists.apache.org/thread/088ddsbrzhd5lxzbqf5n24yg0mwh9jt2 vendor-advisory