How severe is CVE-2017-5637?

CVE-2017-5637 has a CVSS score of 7.5/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2017-5637?

CVE-2017-5637 affects the following packages: org.apache.zookeeper:zookeeper (Maven), org.apache.zookeeper:zookeeper (Maven). Ecosystems affected: Maven.

How do I fix CVE-2017-5637?

Update org.apache.zookeeper:zookeeper to 3.4.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2017-5637 is resolved across your whole dependency graph.

How do I detect CVE-2017-5637 in my Maven dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.zookeeper:zookeeper, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2017-5637 if there is no patch (or I can't update yet)?

Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Is CVE-2017-5637 actively exploited in the wild?

Yes. There are 1 known exploit references for CVE-2017-5637, including 1 documented proof-of-concept exploit on Exploit-DB. Treat this as actively exploitable and prioritize patching immediately. All exploit code should only be run in an isolated sandbox environment for research or authorized testing — never against production systems without explicit written authorization.

What is the EPSS score for CVE-2017-5637?

CVE-2017-5637 has an EPSS (Exploit Prediction Scoring System) score of 73.1%, placing it in the 99th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. A score above 50% indicates significantly elevated exploitation risk — immediate patching is strongly recommended.

What type of vulnerability is CVE-2017-5637?

CVE-2017-5637 is classified as Missing Authentication (CWE-306), Uncontrolled Resource Consumption (CWE-400). These weakness types describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2017-5637 published, and has it been updated?

CVE-2017-5637 was published on October 10, 2017 and was last updated on October 24, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

☕

☕ Maven

Not in CISA KEV

HIGH severity

CVE-2017-5637 — zookeeper

HIGH

CVE-2017-5637 is a high-severity (CVSS 7.5) Missing Authentication vulnerability in org.apache.zookeeper:zookeeper. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. A fix is available for org.apache.zookeeper:zookeeper — see the affected versions and patch details below.

Uncontrolled Resource Consumption in Apache ZooKeeper

Also known asGHSA-7cwj-j333-x7f7

Published

Oct 10, 2017

Updated

Oct 24, 2026

Affected

2 pkgs

Patched

2 / 2

Exploits

1 known

Exploitation data as of Nov 5, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

73.1%probability of exploitation in next 30 days

Very High Risk0.00%

Lower risk than most CVEs99th percentile — riskier than 99% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

2 pkgs affected

☕org.apache.zookeeper:zookeeper☕org.apache.zookeeper:zookeeper

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

Two four letter word commands "wchp/wchc" are CPU intensive and could cause spike of CPU utilization on Apache ZooKeeper server if abused, which leads to the server unable to serve legitimate client requests. Apache ZooKeeper thru version 3.4.9 and 3.5.2 suffer from this issue, fixed in 3.4.10, 3.5.3, and later.

Affected Packages

2 total 2 fixed

Ecosystem	Package	Vulnerable range	Fix
☕Maven	`org.apache.zookeeper:zookeeper`	≥ 3.4.0&&< 3.4.10	3.4.10`org.apache.zookeeper:zookeeper:3.4.10`
☕Maven	`org.apache.zookeeper:zookeeper`	≥ 3.5.0&&< 3.5.3	3.5.3`org.apache.zookeeper:zookeeper:3.5.3`

Affected Products

2 products · 14 configurations

Application

zookeeperapache

13 versions

3.4.03.4.13.4.23.4.33.4.43.4.53.4.63.4.73.4.83.4.93.5.03.5.1

debian linuxdebian

1 version

8.0

Exploits & PoCs

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

EDB-42294dosmultiple

Zookeeper 3.5.2 Client - Denial of Service

by Brandon Dennis · Jul 2, 2017

Exploit-DB Source

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.zookeeper:zookeeper, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.apache.zookeeper:zookeeper to 3.4.10 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2017-5637 is resolved across your whole dependency graph.
Workarounds
Put an independent control in front of the weakness: restrict the affected endpoint or interface to trusted networks, require an additional authentication factor or proxy-level check, and invalidate existing sessions and credentials in case the flaw has already been used.

Fixing This On Your OS

If you run this on a Linux distribution, patch through your package manager against the distro's own security advisory below — it tracks the exact backported fix for your release, which can ship on a different timeline (and sometimes a different severity) than the upstream project.

Red HatModerate

Product	Fixed in	Advisory
Red Hat JBoss BPMS 6.4	`zookeeper`	RHSA-2017:3355
Red Hat JBoss BRMS 6.4	`zookeeper`	RHSA-2017:3354
Red Hat JBoss Data Virtualization 6.3	`zookeeper`	RHSA-2017:2477

UbuntuHIGH

USN-4789-1Ubuntu

Frequently Asked Questions

O3 Security · Impact-Aware SCA

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