How severe is CVE-2017-5637?

CVE-2017-5637 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2017-5637 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 73% (99th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2017-5637?

CVE-2017-5637 primarily affects Apache Zookeeper. In total, 14 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2017-5637?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2017-5637 published?

CVE-2017-5637 was published on 2017-10-10 and last updated on 2026-06-17.

CVE-2017-5637

CVE-2017-5637 is a high-severity vulnerability in Apache Zookeeper with a CVSS 3.x base score of 7.5. Its EPSS exploit-prediction score of 73% places it in the 99th percentile, indicating an elevated likelihood of exploitation. The underlying weakness is classified as CWE-306.

Key facts

Severity: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 73% (99th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-306
Affected product: Apache Zookeeper
Published: 2017-10-10
Last modified: 2026-06-17

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.

Frequently asked questions

What is CVE-2017-5637?: 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 severe is CVE-2017-5637?: CVE-2017-5637 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2017-5637 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 73% (99th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2017-5637?: CVE-2017-5637 primarily affects Apache Zookeeper. In total, 14 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2017-5637?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2017-5637 published?: CVE-2017-5637 was published on 2017-10-10 and last updated on 2026-06-17.

References

Affected products (14)

cpe:2.3:a:apache:zookeeper:3.4.0:*:*:*:*:*:*:*
cpe:2.3:a:apache:zookeeper:3.4.1:*:*:*:*:*:*:*
cpe:2.3:a:apache:zookeeper:3.4.2:*:*:*:*:*:*:*
cpe:2.3:a:apache:zookeeper:3.4.3:*:*:*:*:*:*:*
cpe:2.3:a:apache:zookeeper:3.4.4:*:*:*:*:*:*:*
cpe:2.3:a:apache:zookeeper:3.4.5:*:*:*:*:*:*:*
cpe:2.3:a:apache:zookeeper:3.4.6:*:*:*:*:*:*:*
cpe:2.3:a:apache:zookeeper:3.4.7:*:*:*:*:*:*:*
cpe:2.3:a:apache:zookeeper:3.4.8:*:*:*:*:*:*:*
cpe:2.3:a:apache:zookeeper:3.4.9:*:*:*:*:*:*:*
cpe:2.3:a:apache:zookeeper:3.5.0:*:*:*:*:*:*:*
cpe:2.3:a:apache:zookeeper:3.5.1:*:*:*:*:*:*:*
cpe:2.3:a:apache:zookeeper:3.5.2:*:*:*:*:*:*:*
cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*

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