CVE-2026-24281
Apache ZooKeeper: Reverse-DNS fallback enables hostname verification bypass in ZooKeeper ZKTrustManager
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.
INFO
Published Date :
March 7, 2026, 9:16 a.m.
Last Modified :
March 10, 2026, 6:18 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | [email protected] | ||||
| CVSS 3.1 | MEDIUM | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
Solution
- Upgrade Apache ZooKeeper to version 3.8.6 or 3.9.5.
- Disable reverse DNS lookup in client and quorum protocols.
- Ensure PTR records are validated where applicable.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-24281.
| URL | Resource |
|---|---|
| https://lists.apache.org/thread/088ddsbrzhd5lxzbqf5n24yg0mwh9jt2 | Mailing List Vendor Advisory |
| http://www.openwall.com/lists/oss-security/2026/03/07/4 | Mailing List Third Party Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-24281 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-24281
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-24281 vulnerability anywhere in the article.
-
CybersecurityNews
Apache ZooKeeper Vulnerability Allow Attackers to Access Sensitive Data
Apache ZooKeeper Vulnerability Two “Important” severity vulnerabilities have been disclosed in Apache ZooKeeper, a widely used service for configuration management and naming in distributed applicatio ... Read more
-
Daily CyberSecurity
Critical Bypasses and Secret Leaks Patched in Apache ZooKeeper
The Apache Software Foundation has released an urgent security update for Apache ZooKeeper, the mission-critical service used by thousands of distributed applications for configuration, naming, and sy ... Read more
The following table lists the changes that have been made to the
CVE-2026-24281 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Mar. 10, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N -
Initial Analysis by [email protected]
Mar. 10, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N Added CWE CWE-295 Added CPE Configuration OR *cpe:2.3:a:apache:zookeeper:*:*:*:*:*:*:*:* versions from (including) 3.8.0 up to (excluding) 3.8.6 *cpe:2.3:a:apache:zookeeper:*:*:*:*:*:*:*:* versions from (including) 3.9.0 up to (excluding) 3.9.5 Added Reference Type Apache Software Foundation: https://lists.apache.org/thread/088ddsbrzhd5lxzbqf5n24yg0mwh9jt2 Types: Mailing List, Vendor Advisory Added Reference Type CVE: http://www.openwall.com/lists/oss-security/2026/03/07/4 Types: Mailing List, Third Party Advisory -
CVE Modified by af854a3a-2127-422b-91ae-364da2661108
Mar. 07, 2026
Action Type Old Value New Value Added Reference http://www.openwall.com/lists/oss-security/2026/03/07/4 -
New CVE Received by [email protected]
Mar. 07, 2026
Action Type Old Value New Value Added 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. Added CWE CWE-295 Added CWE CWE-350 Added Reference https://lists.apache.org/thread/088ddsbrzhd5lxzbqf5n24yg0mwh9jt2