High
Security advisory
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.
- Products
- Not specified
- Affected versions
- Not specified
- Fixed versions
- Not specified
- CVEs
- CVE-2017-5637
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 1 Nov 2026, 07:29 UTC · Revision 1
Source evidence
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.
osv:CVE-2017-5637
Complete source record
{
"id": "8cabc81d44bd7fa4e47ce9b7eb7b8909ba65cc62735737f58185ba1a661cd38c",
"url": "https://osv.dev/vulnerability/CVE-2017-5637",
"method": "structured",
"payload": {
"kind": "advisory",
"title": "CVE-2017-5637",
"summary": "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.",
"evidence": "osv:CVE-2017-5637",
"products": [],
"severity": "high",
"structured": {
"id": "CVE-2017-5637",
"aliases": [
"CVE-2017-5637",
"GHSA-7cwj-j333-x7f7"
],
"metrics": [
{
"type": "CVSS_V3",
"score": "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H"
}
],
"affected": [
{
"ranges": [
{
"repo": "https://github.com/apache/zookeeper",
"type": "GIT",
"events": [
{
"introduced": "2109aca0fa091222434a8895e2533a26b770ad05"
},
{
"last_affected": "3f572f0a3568ad21d7a1175ecde007b222c74cf4"
}
],
"database_specific": {
"extracted_events": [
{
"cpe": "cpe:2.3:a:apache:zookeeper:3.4.0:*:*:*:*:*:*:*",
"range": [
{
"introduced": "3.4.0"
},
{
"last_affected": "3.4.0"
}
],
"source": "CPE_STRING"
},
{
"cpe": "cpe:2.3:a:apache:zookeeper:3.4.1:*:*:*:*:*:*:*",
"range": [
{
"introduced": "3.4.1"
},
{
"last_affected": "3.4.1"
}
],
"source": "CPE_STRING"
},
{
"cpe": "cpe:2.3:a:apache:zookeeper:3.4.2:*:*:*:*:*:*:*",
"range": [
{
"introduced": "3.4.2"
},
{
"last_affected": "3.4.2"
}
],
"source": "CPE_STRING"
},
{
"cpe": "cpe:2.3:a:apache:zookeeper:3.4.3:*:*:*:*:*:*:*",
"range": [
{
"introduced": "3.4.3"
},
{
"last_affected": "3.4.3"
}
],
"source": "CPE_STRING"
},
{
"cpe": "cpe:2.3:a:apache:zookeeper:3.4.4:*:*:*:*:*:*:*",
"range": [
{
"introduced": "3.4.4"
},
{
"last_affected": "3.4.4"
}
],
"source": "CPE_STRING"
},
{
"cpe": "cpe:2.3:a:apache:zookeeper:3.4.5:*:*:*:*:*:*:*",
"range": [
{
"introduced": "3.4.5"
},
{
"last_affected": "3.4.5"
}
],
"source": "CPE_STRING"
},
{
"cpe": "cpe:2.3:a:apache:zookeeper:3.4.6:*:*:*:*:*:*:*",
"range": [
{
"introduced": "3.4.6"
},
{
"last_affected": "3.4.6"
}
],
"source": "CPE_STRING"
},
{
"cpe": "cpe:2.3:a:apache:zookeeper:3.4.7:*:*:*:*:*:*:*",
"range": [
{
"introduced": "3.4.7"
},
{
"last_affected": "3.4.7"
}
],
"source": "CPE_STRING"
},
{
"cpe": "cpe:2.3:a:apache:zookeeper:3.4.8:*:*:*:*:*:*:*",
"range": [
{
"introduced": "3.4.8"
},
{
"last_affected": "3.4.8"
}
],
"source": "CPE_STRING"
},
{
"cpe": "cpe:2.3:a:apache:zookeeper:3.4.9:*:*:*:*:*:*:*",
"range": [
{
"introduced": "3.4.9"
},
{
"last_affected": "3.4.9"
}
],
"source": "CPE_STRING"
},
{
"cpe": "cpe:2.3:a:apache:zookeeper:3.5.0:*:*:*:*:*:*:*",
"range": [
{
"introduced": "3.5.0"
},
{
"last_affected": "3.5.0"
}
],
"source": "CPE_STRING"
},
{
"cpe": "cpe:2.3:a:apache:zookeeper:3.5.1:*:*:*:*:*:*:*",
"range": [
{
"introduced": "3.5.1"
},
{
"last_affected": "3.5.1"
}
],
"source": "CPE_STRING"
},
{
"cpe": "cpe:2.3:a:apache:zookeeper:3.5.2:*:*:*:*:*:*:*",
"range": [
{
"introduced": "3.5.2"
},
{
"last_affected": "3.5.2"
}
],
"source": "CPE_STRING"
}
]
}
}
],
"versions": [
"3.4.0",
"3.4.1",
"3.4.2",
"3.4.3",
"3.4.4",
"3.4.5",
"3.4.6",
"3.4.7",
"3.4.8",
"3.4.9",
"3.5.0",
"3.5.1",
"3.5.2"
],
"database_specific": {
"source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2017-5637.json"
}
}
],
"modified": "2026-10-24T10:30:54.148012420Z",
"provider": "osv",
"references": [
"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",
"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"
],
"provider_metadata": {
"unresolved_ranges": [
{
"cpes": [
"cpe:2.3:o:debian:debian_linux:8.0:*:*:*:*:*:*:*"
],
"vendor_product": "debian:debian_linux",
"extracted_events": [
{
"range": [
{
"introduced": "8.0"
},
{
"last_affected": "8.0"
}
],
"source": "CPE_STRING"
}
]
}
]
}
},
"related_cves": [
{
"value": "CVE-2017-5637",
"evidence": "/id"
}
],
"security_relevant": true,
"severity_evidence": "/severity/0/score"
},
"source_id": "core-osv",
"document_id": 438093,
"published_at": "2017-10-10T01:30:22.36+00:00"
}