CVE & CISA-KEV Catalog

CVE-2017-5637

HIGHEPSS 99th pctl
7.5
CVSS v3
NVD

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.

How to fix

Remediation Available
zookeeperDebian
Fixed in:3.4.9-3CVE-2017-5637
Fixed in:3.4.9-3CVE-2017-5637
Fixed in:3.4.9-3CVE-2017-5637
Fixed in:3.4.9-3CVE-2017-5637
libzookeeper-javaUbuntu
Fixed in:3.4.5+dfsg-1ubuntu0.1~esm1USN-4789-1
Fixed in:3.4.8-1ubuntu0.1~esm1USN-4789-1
libzookeeper-mt2Ubuntu
Fixed in:3.4.5+dfsg-1ubuntu0.1~esm1USN-4789-1
Fixed in:3.4.8-1ubuntu0.1~esm1USN-4789-1
libzookeeper-st2Ubuntu
Fixed in:3.4.5+dfsg-1ubuntu0.1~esm1USN-4789-1
Fixed in:3.4.8-1ubuntu0.1~esm1USN-4789-1
libzookeeper2Ubuntu
Fixed in:3.4.5+dfsg-1ubuntu0.1~esm1USN-4789-1
Fixed in:3.4.8-1ubuntu0.1~esm1USN-4789-1
python-zookeeperUbuntu
Fixed in:3.4.5+dfsg-1ubuntu0.1~esm1USN-4789-1
Fixed in:3.4.8-1ubuntu0.1~esm1USN-4789-1
zookeeperUbuntu
Fixed in:3.4.5+dfsg-1ubuntu0.1~esm1USN-4789-1
Fixed in:3.4.8-1ubuntu0.1~esm1USN-4789-1
zookeeper-binUbuntu
Fixed in:3.4.5+dfsg-1ubuntu0.1~esm1USN-4789-1
Fixed in:3.4.8-1ubuntu0.1~esm1USN-4789-1
zookeeperdUbuntu
Fixed in:3.4.5+dfsg-1ubuntu0.1~esm1USN-4789-1
Fixed in:3.4.8-1ubuntu0.1~esm1USN-4789-1

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Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityNone
IntegrityNone
AvailabilityHigh

CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Exploit Intelligence

72.88%probability of exploitation in 30 days
99thpercentile

Very high risk: more likely to be exploited than 99% of all known CVEs.

References

Related Vulnerabilities

Other CWE-306 (Missing Authentication for Critical Function) vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2025-3248Critical9.8100%KEV + RansomFix
CVE-2017-10271High7.5100%KEV + Ransom-
CVE-2023-42793Critical9.8100%KEV + RansomFix
CVE-2022-1388Critical9.8100%KEV + RansomFix
CVE-2026-33017Critical9.8100%KEVFix
CVE-2021-37415Critical9.8100%KEV-

Common questions

How do I fix CVE-2017-5637?

Published advisories record a fix for 9 affected products. The "How to fix" section on this page lists the fixed version and source advisory for each one, so apply the entry matching what you actually run.

Is CVE-2017-5637 being actively exploited?

Not that we know of. CVE-2017-5637 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 72.9% is the estimated probability that it will be exploited in the next 30 days. That is higher than 99% of all scored CVEs.

How severe is CVE-2017-5637?

CVE-2017-5637 has a CVSS v3 base score of 7.5, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2017-5637 affect?

Published advisories record a fix for zookeeper (Debian), libzookeeper-java (Ubuntu), libzookeeper-mt2 (Ubuntu), libzookeeper-st2 (Ubuntu), and 5 more. Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-05-13.