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ZookeeperApplication · Apache

CVE-2023-44981

CRITICAL · 9.1 CVSS v3.1 Published 2023-10-11
Fix available
A fix is available. Upgrade to 3.7.2 / 3.8.3 or later.
See remediation →
100/100
Remediation priority · Urgent
Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
Authorization Bypass Through User-Controlled Key vulnerability in Apache ZooKeeper. If SASL Quorum Peer authentication is enabled in ZooKeeper (quorum.auth.enableSasl=true), the authorization is done by verifying that the instance part in SASL authentication ID is listed in zoo.cfg server list. The instance part in SASL auth ID is optional and if it's missing, like '[email protected]', the authorization check will be skipped. As a result an arbitrary endpoint could join the cluster and begin propagating counterfeit changes to the leader, essentially giving it complete read-write access to the data tree. Quorum Peer authentication is not enabled by default. Users are recommended to upgrade to version 3.9.1, 3.8.3, 3.7.2, which fixes the issue. Alternately ensure the ensemble election/quorum communication is protected by a firewall as this will mitigate the issue. See the documentation for more details on correct cluster administration.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Apache ZooKeeper has an authorization bypass when SASL Quorum Peer authentication is enabled. The instance portion of the SASL authentication ID is optional, and when absent (e.g., '[email protected]' instead of 'eve/[email protected]'), the authorization check that verifies the instance is in the zoo.cfg server list is skipped entirely. This allows any endpoint to join the quorum and gain full read-write access to the data tree.

MitigationUpgrade ZooKeeper to version 3.9.1, 3.8.3, or 3.7.2, or protect quorum communication with a firewall if upgrading is not immediately feasible.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
ZookeeperApplication
Affected:< 3.7.2>= 3.8.0, < 3.8.3= 3.9.0
Debian LinuxOperating system
Affected:= 10.0= 11.0= 12.0

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check installed ZooKeeper version
    Run 'zookeeper-server version' or check the package manager (apt list --installed 2>/dev/null | grep zookeeper, rpm -qi zookeeper, or look for the jar file version in /usr/share/zookeeper)
    Affected if Version is < 3.7.2, or >= 3.8.0 and < 3.8.3, or exactly 3.9.0
  2. Verify SASL Quorum authentication is configured
    Examine zoo.cfg (commonly in /etc/zookeeper/conf/ or /opt/zookeeper/conf/) and look for 'authProvider' entries with 'org.apache.zookeeper.server.auth.SASLAuthenticationProvider' or SASL-related settings like 'quorum.auth.enabled', 'quorum.auth.learnerWithSasl', or 'quorum.auth.server.sASLEnabled'
    Affected if SASL authentication for quorum peers is enabled in the configuration
  3. Confirm server list exists in zoo.cfg
    Check zoo.cfg for 'server.N=' entries in the 'server' list used for quorum configuration
    Affected if A server list is present - the bypass occurs when the instance portion of SASL ID is omitted and the server list check is skipped
  4. Check if ZooKeeper is exposed to untrusted networks
    Review firewall rules or network binding settings (clientPortAddress, adminServerPort) and determine if quorum communication ports (2888, 3888 by default) are accessible from untrusted networks
    Affected if ZooKeeper quorum ports are reachable from networks without explicit trust boundaries

You are affected if ZooKeeper version is vulnerable AND SASL Quorum authentication is enabled, because the authorization bypass allows any host claiming a SASL principal without an instance component to join the quorum.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 3.7.2 / 3.8.3 or later
Fixed in 3.7.23.8.3
Interim mitigation

Upgrade ZooKeeper to version 3.9.1, 3.8.3, or 3.7.2, or protect quorum communication with a firewall if upgrading is not immediately feasible.

Recommended fix High confidence

3.9.1 (or 3.8.3, 3.7.2)

  1. 1. Backup your ZooKeeper configuration and data directories before proceeding with the upgrade.
  2. 2. Stop all ZooKeeper servers in your ensemble to prevent data inconsistency.
  3. 3. Download the fixed ZooKeeper version (3.9.1, 3.8.3, or 3.7.2) from the official Apache ZooKeeper releases.
  4. 4. Replace the existing ZooKeeper installation with the new version on all nodes in the ensemble.
  5. 5. Restore your zoo.cfg configuration file from the backup.
  6. 6. Verify that SASL Quorum Peer authentication is properly configured if you use it; ensure the instance ID is correctly specified in the server list.
  7. 7. Start ZooKeeper servers sequentially, allowing each node to fully join the ensemble before starting the next.
  8. 8. Verify the cluster is healthy using the 'stat' four-letter command or via the admin interface.
Caveat Standard upgrade risks apply - test in staging first; ensure client compatibility with new ZooKeeper version

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Zookeeper Scoped from the published advisory
  • Consultation4.0 h
  • Implementation8.0 h
  • Testing4.0 h
  • Review / QA2.0 h
18.0 hours of engineering $3,200
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-44981 in production — separate from our analysis above.

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What this is

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What belongs here
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  • Version or environment caveats, and links to real fixes
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