No exploitation reported

CVE-2017-5637

No exploitation reported by the sources we read.

Published2017-10-10
WeaknessCWE-306 · CWE-400

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC

2017-10-1001:30CVE publishedNVD
2026-10-2319:23EPSS crossed 10 %FIRST EPSS

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2017-5637?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2017-5637?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Apache zookeeper

Branch	Affected	Fixed in	Source
3.4	= 3.4.0	no fix published	NVD
3.4	= 3.4.1	no fix published	NVD
3.4	= 3.4.2	no fix published	NVD
3.4	= 3.4.3	no fix published	NVD
3.4	= 3.4.4	no fix published	NVD
3.4	= 3.4.5	no fix published	NVD
3.4	= 3.4.6	no fix published	NVD
3.4	= 3.4.7	no fix published	NVD
3.4	= 3.4.8	no fix published	NVD
3.4	= 3.4.9	no fix published	NVD
3.5	= 3.5.0	no fix published	NVD
3.5	= 3.5.1	no fix published	NVD

Debian debian linux

Branch	Affected	Fixed in	Source
8.0	= 8.0	no fix published	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Advisories and patches

issues.apache.orgMitigation · Vendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

NVDCVSS 3.07.5read 2026-10-23
NVDCVSS 2.05read 2026-10-23
NVDweakness (CWE)CWE-306, CWE-400read 2026-10-23
FIRST EPSSEPSS score73.1 %read 2026-10-23

Technical details

CVSS v3 Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Published: 2017-10-10
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2017-5637?

Is CVE-2017-5637 actively exploited?

Active exploitation of CVE-2017-5637 has not been confirmed. Its EPSS score was 73.1% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

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

CVE-2017-5637 has a CVSS v3 base score of 7.5 (HIGH severity), with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

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