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  4. CVE 2026 100300 apache zookeeper unauthenticated persistent
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Back to active CVEs
High · CVSS 8.7CVE-2026-100300

Apache ZooKeeper: Unauthenticated persistent denial of service via unvalidated quota-node data and paths crashing the transaction-apply threadCVE-2026-100300

Answer in brief

CVE-2026-100300 records a High severity (CVSS 8.7) vulnerability in Apache ZooKeeper: Unauthenticated persistent denial of service via unvalidated quota-node data and paths crashing the transaction-apply thread. The current sources do not mark it as known exploited. The current feed maps Apache Software Foundation/org.apache.zookeeper:zookeeper (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Nov 4, 2026Updated Nov 4, 2026Source checked Nov 4, 2026First seen by HOL Nov 4, 2026Material review Nov 4, 2026
Upstream Advisory

Key facts

Risk
High · CVSS 8.7
Exploitation
Not marked as known exploited
Affected software
1 mapped package or product
Fix availability
Not reported

Why this deserves its current priority

CVSS is 8.7. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps Apache Software Foundation/org.apache.zookeeper:zookeeper (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
PackageAffected rangeFixed version
Apache Software Foundation/org.apache.zookeeper:zookeepergeneric>=3.9.0 <=3.9.6 || >=3.8.0 <=3.8.7Not reported

Recommended response

  1. 1Check inventory. Check lockfiles and deployed manifests for Apache Software Foundation/org.apache.zookeeper:zookeeper.
  2. 2Review the reported fix. Monitor this advisory for an available fix and review any installs of the affected package.

Evidence timeline and material changes

  1. Published upstream

    Nov 4, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  2. Source modified

    Nov 4, 2026

    Evidence: source:cvelist:source_dates:source-dates:record

  3. First seen by HOL

    Nov 4, 2026

Sources and claim methodology

  • Source referencelists.apache.org
  • Source referenceopenwall.com
Upstream source description

Improper handling of exceptional conditions in the quota subsystem of Apache ZooKeeper allows an attacker able to write under the /zookeeper/quota subtree — unauthenticated on default deployments, where that subtree is world-writable — to crash the server's critical request-processing thread and render the on-disk data directory permanently unbootable. This issue affects Apache ZooKeeper up to and including 3.9.6. Users are recommended to upgrade to version 3.8.8 or 3.9.7, which fixes the issue.

Quoted source text, attributed separately from HOL analysis.

Related CVEs

  • Apache ZooKeeper: ACL enforcement bypass allows unauthorized operations to commit after an ACL revocationSame apache software foundation/org.apache.zookeeper package
  • Apache ZooKeeper: SASL authorization bypass on the client port through a client-supplied authorization IDSame apache software foundation/org.apache.zookeeper package
  • Apache ZooKeeper: Denial of service through unbounded memory allocation in multiRead request handlingSame apache software foundation/org.apache.zookeeper package
  • Apache ZooKeeper: Unbounded recursion in snapshot serialization allows a client to render the server unrecoverableSame apache software foundation/org.apache.zookeeper package

Record context

Vulnerability class
Missing Auth
EPSS
Not reported
CWE IDs
CWE-755
Source
CVE List V5
Source checked
Nov 4, 2026
References
2 linked sources
Open source record