CVE-2017-5637

Severity: high (CVSS 7.5 v3.0)
Exploited in the wild: not listed in CISA KEV
EPSS: 73.1% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2017-10-10 · updated 2026-06-17
Weakness: CWE-306

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 products

Apache Software Foundation Apache ZooKeeper: 3.4.0, 3.4.1, 3.4.2, 3.4.3, 3.4.4, 3.4.5 (+7)
Debian Linux: 8.0

References

http://www.debian.org/security/2017/dsa-3871
http://www.securityfocus.com/bid/98814
https://access.redhat.com/errata/RHSA-2017:2477
https://access.redhat.com/errata/RHSA-2017:3354
https://access.redhat.com/errata/RHSA-2017:3355
https://issues.apache.org/jira/browse/ZOOKEEPER-2693
https://lists.apache.org/thread.html/053d9ce4d579b02203db18545fee5e33f35f2932885459b74d1e4272%40%3Cissues.activemq.apache.org%3E
https://lists.apache.org/thread.html/58170aeb7a681d462b7fa31cae81110cbb749d2dc83c5736a0bb8370%40%3Cdev.zookeeper.apache.org%3E
https://lists.apache.org/thread.html/bcce5a9c532b386c68dab2f6b3ce8b0cc9b950ec551766e76391caa3%40%3Ccommits.nifi.apache.org%3E
https://lists.apache.org/thread.html/rca37935d661f4689cb4119f1b3b224413b22be161b678e6e6ce0c69b%40%3Ccommits.nifi.apache.org%3E
https://www.oracle.com//security-alerts/cpujul2021.html
https://www.oracle.com/security-alerts/cpujul2020.html

Get alerted when CVE-2017-5637 or the next vulnerability affects your stack