CVE-2017-5637

Exp

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.

Published: 2017-10-10 Last update: 2026-05-13 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2017-5637 is rated High Exploit Risk (84.8/100): CVSS High severity, with high exploitation likelihood (EPSS 73.65%, 99th percentile). 1 public exploit reference(s) are indexed (Exploit-DB). EPSS rose +56.21% over the last day, indicating growing attacker interest. Public exploits are available—assess exposure, apply mitigations, and prioritize patching.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Public exploit references (Exploit-DB) for CVE-2017-5637

EDB-ID Source Kind Published Link
42294 exploit_db edb 2017-07-02 Exploit-DB ↗

Exploit prediction scoring system (EPSS) score for CVE-2017-5637

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 17.45% 73.65% +56.21%
2 2025-11-21 42.96% 17.45% -25.51%
3 2025-11-18 — 42.96% —

Full EPSS history (18 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2017-5637

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.0 HIGH
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
5.0 2.0 MEDIUM
AV:N/AC:L/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:L)
Exploitation conditions are straightforward and predictable.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 10.0 2.9 [email protected]

Weakness enumeration for CVE-2017-5637

GitHub Security Advisory for CVE-2017-5637

GHSA-7cwj-j333-x7f7 · Severity: high · Ecosystem: maven — Uncontrolled Resource Consumption in Apache ZooKeeper

OS Trackers for CVE-2017-5637

vendor priority summary link
debian not yet assigned CVE-2017-5637 not yet assigned priority: Debian including 1 source packages (zookeeper), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2017-5637
redhat medium — https://access.redhat.com/security/cve/CVE-2017-5637
ubuntu medium CVE-2017-5637 medium priority: Ubuntu including 1 source packages (zookeeper), 15 status rows across 15 suites (artful, bionic, cosmic, disco, eoan, focal, groovy, hirsute, impish, jammy, trusty, upstream, xenial, yakkety, zesty): not-affected 9, ignored 3, released 3. https://ubuntu.com/security/CVE-2017-5637

Affected software / configurations for CVE-2017-5637

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

References for CVE-2017-5637

URL Tags
http://www.debian.org/security/2017/dsa-3871 Third Party Advisory
http://www.securityfocus.com/bid/98814 Third Party Advisory VDB Entry
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 Issue Tracking Mitigation Vendor Advisory
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
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