CVE-2023-44981Network attack vector

Cluster read-write access via missing SASL instance

Published Oct 11, 2023 · Updated Apr 23, 2025

Authorization bypass in Apache ZooKeeper before 3.7.2, 3.8.0 through 3.8.2, and 3.9.0 allows remote attackers to read and write cluster data. The quorum peer authorization check treats the SASL identity's instance component as optional and skips server-list validation when it is absent. Exploitation requires the nondefault quorum.auth.enableSasl setting and network access to an ensemble quorum port, after which an endpoint can join the cluster and propagate counterfeit changes.

CVSS severity9.1
Critical
EPSS probability1.71%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
Coverage for this vulnerability

See if you're affected

Explore vulnerability checks for your environment with Hinoki.

Book a demo

Summary

What happened

Authorization bypass in Apache ZooKeeper before 3.7.2, 3.8.0 through 3.8.2, and 3.9.0 allows remote attackers to read and write cluster data. The quorum peer authorization check treats the SASL identity's instance component as optional and skips server-list validation when it is absent. Exploitation requires the nondefault quorum.auth.enableSasl setting and network access to an ensemble quorum port, after which an endpoint can join the cluster and propagate counterfeit changes.

The record

CVE
CVE-2023-44981
Published
Oct 11, 2023
Updated
Apr 23, 2025
Vendor
The Apache Software Foundation
Product
Apache ZooKeeper
Classifications
CWE-639, T1190
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Oct 11, 2023CVE publishedPublication date reported by the CVE source.
  2. Apr 23, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0 <3.7.0
  2. Affected versionversion=3.7.0 <=3.7.1
  3. Affected versionversion=3.8.0 <=3.8.2
  4. Affected versionversion=3.9.0 <3.9.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

The Apache Software Foundation · Apache ZooKeeperversion=0 <3.7.0; version=3.7.0 <=3.7.1; version=3.8.0 <=3.8.2; version=3.9.0 <3.9.1

Published CVSS scores

9.1GitHub Advisory DatabaseCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-639Authorization Bypass Through User-Controlled Key
T1190Exploit Public-Facing Application

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

See the directory against your own environment.

Your stack

Check the software in your environment

Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.

Book a demo