CVE-2017-5637: Uncontrolled Resource Consumption in Apache ZooKeeper
Summary
CVE-2017-5637: Uncontrolled Resource Consumption in Apache ZooKeeper. Affects org.apache.zookeeper:zookeeper across 2 version ranges.
>= 3.4.0, < 3.4.10
>= 3.5.0, < 3.5.3
Fixed in 3.4.10 or 3.5.3, depending on the release line you run. How to fix ↓
Also tracked for
- zookeeper · Debian:11
The same CVE-2017-5637 is tracked separately for each ecosystem and vendor. Its fix information is the same; the package and affected versions differ.
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Background
Apache ZooKeeper is a distributed coordination service that enables synchronization across a cluster of servers. It provides a hierarchical key-value store, similar to a file system, that can be accessed by multiple clients. ZooKeeper is widely used in distributed systems to maintain configuration information, provide distributed synchronization, and offer group services. However, versions 3.4.0 to 3.4.9 and 3.5.0 to 3.5.2 of Apache ZooKeeper are vulnerable to uncontrolled resource consumption.
Vulnerability Detail
The vulnerability in Apache ZooKeeper arises from two specific four-letter word commands, namely "wchp/wchc." These commands are CPU intensive and can cause a spike in CPU utilization on the ZooKeeper server if abused. As a result, the server becomes unable to serve legitimate client requests. This vulnerability has the potential to disrupt the normal functioning of the ZooKeeper service and impact the availability of the distributed systems relying on it. The issue has been fixed in versions 3.4.10, 3.5.3, and later.
How To Fix
Latest published version: 3.9.6 as of 22 Oct 2026
Upgrading to it may include breaking changes; the versions below are the minimum fixed release for this vulnerability.
If you can't move to the latest
The minimum fixed version depends on the release line you run.
-
>= 3.4.0, < 3.4.103.4.10 -
>= 3.5.0, < 3.5.33.5.3
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Workaround
There is no specific workaround available for this vulnerability. Upgrading to the fixed versions is the recommended solution.
Conclusion
The uncontrolled resource consumption vulnerability in Apache ZooKeeper can lead to a spike in CPU utilization, impacting the availability of distributed systems relying on ZooKeeper. It is crucial to upgrade to the fixed versions (3.4.10, 3.5.3, or later) to mitigate this issue. For further support on vulnerability remediation, please contact DevNack.com.
See every vulnerability recorded for org.apache.zookeeper:zookeeper →
FAQ
Apache ZooKeeper is a distributed coordination service that provides synchronization across a cluster of servers. It is commonly used in distributed systems for maintaining configuration information, distributed synchronization, and group services.
The vulnerability can lead to a spike in CPU utilization on the Apache ZooKeeper server, rendering it unable to serve legitimate client requests. This can disrupt the normal functioning of distributed systems relying on ZooKeeper.
Versions 3.4.0 to 3.4.9 and 3.5.0 to 3.5.2 of Apache ZooKeeper are affected by this vulnerability.
To fix this vulnerability, upgrade Apache ZooKeeper to version 3.4.10 or 3.5.3, or any subsequent release.
No, there is no specific workaround available for this vulnerability. Upgrading to the fixed versions is the recommended solution.
Related vulnerabilities
Recent vulnerabilities recorded for org.apache.zookeeper:zookeeper.
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