# Cis Tomcat101 10.16

> Enable memory leak listener (Automated)

- Skill: `cyberstrikeus/cis-tomcat101-10-16` (Agent Skill)
- Install (CLI): `npx skillmds@latest add cyberstrikeus/cis-tomcat101-10-16`
- Raw SKILL.md: https://api.skillmd.com/api/skills/cyberstrikeus/cis-tomcat101-10-16/raw
- Safety review: PASS (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: cyberstrikeus (https://skillmd.com/u/cyberstrikeus)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/cyberstrikeus/cis-tomcat101-10-16

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# 10.16 Enable memory leak listener (Automated)

## Description

The JRE Memory Leak Prevention Listener provides work-arounds for known places where the Java Runtime uses the context class loader to load a singleton as this will cause a memory leak if a web application class loader happens to be the context class loader at the time. The work-around is to initialize these singletons when this listener starts as Tomcat's common class loader is the context class loader at that time. It also provides work-arounds for known issues that can result in locked JAR files.

## Rationale

Enabling the JRE Memory Leak Prevention Listener provides work-arounds for preventing memory leaks.

## Audit Procedure

Ensure this line is present and not commented out in the `$CATALINA_HOME/conf/server.xml`:

```xml
<Listener
className="org.apache.catalina.core.JreMemoryLeakPreventionListener" />
```

## Remediation

Uncomment the JRE Memory Leak Prevention Listener in `$CATALINA_HOME/conf/server.xml`

```xml
<Listener
className="org.apache.catalina.core.JreMemoryLeakPreventionListener" />
```

## References

1. https://tomcat.apache.org/tomcat-9.0-doc/config/listeners.html#JRE_Memory_Leak_Prevention_Listener_-_org.apache.catalina.core.JreMemoryLeakPreventionListener

## CIS Controls

| Controls Version | Control                                                                                                                                                                                                                                                                                        | IG 1 | IG 2 | IG 3 |
| ---------------- | ---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------- | ---- | ---- | ---- |
| v8               | 4 Secure Configuration of Enterprise Assets and Software<br>Establish and maintain the secure configuration of enterprise assets (end-user devices, including portable and mobile; network devices; non-computing/IoT devices; and servers) and software (operating systems and applications). |      |      |      |
| v7               | 5.1 Establish Secure Configurations<br>Maintain documented, standard security configuration standards for all authorized operating systems and software.                                                                                                                                       | ●    | ●    | ●    |

## Profile

Level 1