---
id: CVE-2026-91006
title: >-
  Apache Karaf: OS Command Injection in Child-Instance Launch (instance:* /
  InstancesMBean)
summary: "Apache Karaf's instance-management service (InstanceServiceImpl) builds the command line used to launch a child Karaf JVM by string concatenation, then executes it through\_/bin/sh\_(Unix) or\_cscript\_(Windows). The caller-supplied\_javaOpts…"
severity: none
cwe:
  - CWE-78
vendor: Apache Software Foundation
product: 'org.apache.karaf:org.apache.karaf.instance.core'
affected:
  - 'org.apache.karaf:org.apache.karaf.instance.core < 4.4.12'
published: '2026-09-28'
updated: '2026-09-28'
sourceUpdated: '2026-09-28T10:44:32.652Z'
source: CVEORG
sourceUrl: 'https://www.cve.org/CVERecord?id=CVE-2026-91006'
references:
  - url: 'https://lists.apache.org/thread/olzy0yjw82b20w59vonfjr1x7v5yzocr'
tags:
  - cve.org
ingestedAt: '2026-09-28T11:08:06.673Z'
---

## Overview

Apache Karaf's instance-management service (InstanceServiceImpl) builds the command line used to launch a child Karaf JVM by string concatenation, then executes it through /bin/sh (Unix) or cscript (Windows). The caller-supplied javaOpts value is spliced into that string unquoted. A javaOpts value containing shell metacharacters (;, |, `, $(...)) is interpreted by the shell instead of being passed to the JVM as an option, giving arbitrary OS command execution as the Karaf process user.


Reachable via the shell commands instance:create, instance:start, instance:restart, instance:change-opts, and the equivalent InstanceMBean JMX operations (createInstance, startInstance, changeJavaOpts, cloneInstance).

Mitigation   *  Set karaf.secured.command.compulsory.roles=admin in etc/system.properties to close the fail-open gap for all unconfigured command scopes.
  *  Restrict which principals can reach instance:* commands and InstancesMBean via etc/users.properties role assignments.
  *  Treat javaOpts passed to instance:create/instance:start/instance:change-opts/InstancesMBean as untrusted input only from fully-trusted operators.

## Affected

- `org.apache.karaf:org.apache.karaf.instance.core < 4.4.12`

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.