---
id: CVE-2026-91006
title: "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)"
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: high
cvss: 8.8
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H'
cwe:
  - CWE-78
vendor: apache
product: karaf
affected:
  - karaf < 4.4.12
patched:
  - karaf 4.4.12
published: '2026-09-28'
updated: '2026-10-08'
sourceUpdated: '2026-10-08T19:19:50.990'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-91006'
references:
  - url: 'https://lists.apache.org/thread/olzy0yjw82b20w59vonfjr1x7v5yzocr'
    label: security@apache.org
  - url: 'http://www.openwall.com/lists/oss-security/2026/09/28/3'
    label: af854a3a-2127-422b-91ae-364da2661108
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-91006.json
  - url: 'https://access.redhat.com/security/cve/CVE-2026-91006'
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2542423'
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-91006'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-91006'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
epss: 0.01135
epssPercentile: 0.6633
ssvc:
  exploitation: none
  automatable: 'no'
  technicalImpact: total
  timestamp: '2026-09-29T03:55:20.472246Z'
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

- `karaf < 4.4.12`

## Remediation

Upgrade past the affected range:

- `karaf 4.4.12`

## Vendor advisories

- **Red Hat VEX** · Important · updated 2026-10-02 · [vex](https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-91006.json)