Insecure Java Deserialization in Apache Karaf

Exploitation

No confirmed exploitation recorded. Patch Next marks exploitation only from CISA KEV.

CVSS

8.1 · CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

EPSS

• CVE-2021-41766: 2.03% estimated exploitation activity in the next 30 days; percentile 81.09 (FIRST EPSS, 2026-11-03). This is a model estimate, not proof of exploitation or customer exposure.

As published by the source; long descriptions are shortened.

Apache Karaf allows monitoring of applications and the Java runtime by using the Java Management Extensions (JMX). JMX is a Java RMI based technology that relies on Java serialized objects for client server communication. Whereas the default JMX implementation is hardened against unauthenticated deserialization attacks, the implementation used by Apache Karaf is not protected against this kind of attack. The impact of Java deserialization vulnerabilities strongly depends on the classes that are available within the targets class path. Generally speaking, deserialization of untrusted data does always represent a high security risk and should be prevented. The risk is low as, by default, Karaf uses a limited set of classes in the JMX server class path. It depends of system scoped classes (e.g. jar in the lib folder).

Published by the source

28 Jan 2022, 22:24 UTC

Last modified by the source

25 Sep 2023, 14:50 UTC

Source last checked

26 Oct 2026, 16:12 UTC

1. Revision 1 · created · 26 Oct 2026

   Published from ghsa record GHSA-jh5g-9m4v-9vv9

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# Patch Next advisory brief: CVE-2021-41766

Advisory: Insecure Java Deserialization in Apache Karaf
IDs: CVE-2021-41766, GHSA-jh5g-9m4v-9vv9
Record: https://patchnext.com/advisories/cve-2021-41766 (revision 1, source checked 26 Oct 2026, 16:12 UTC)
Inventory: none attached. This brief comes from a public page and does not say whether any deployment is affected.
Severity: High (CVSS 8.1)
Exploitation: no confirmed exploitation recorded. Patch Next confirms exploitation only from CISA KEV.
Vendor response: Vendor fix available; fixed versions by package: org.apache.karaf.management:org.apache.karaf.management.server 4.3.6. A vendor fix does not mean a deployment is fixed.

## Affected components
- Maven org.apache.karaf.management:org.apache.karaf.management.server: affected < 4.3.6; fixed in 4.3.6

## Suggested inspection (read-only)
- Maven org.apache.karaf.management:org.apache.karaf.management.server: check the installed version with your package manager.

## Supported action
Upgrade each affected component to a fixed version on its release line. For a transitive dependency, upgrade the parent package or add an override or constraint, then regenerate the lockfile. Redeploy every environment that ran an affected version.

## Required regression checks
- Run the test suite and a production build.
- Exercise the features that depend on org.apache.karaf.management:org.apache.karaf.management.server.
- Repeat the inspection and confirm that only fixed versions remain installed.

## Rollback considerations
- Keep the previous lockfile and deployment artifact. Rolling back reinstates the vulnerable version, so apply any documented mitigation while you fix forward.

## Unresolved questions
- Which deployments run an affected version?
- Exploitation status can change. Check again before lowering the priority.
- Mark the work resolved only after the fixed version is verified in production.

## Sources
- Verified: https://github.com/advisories/GHSA-jh5g-9m4v-9vv9 (GitHub-reviewed advisory GHSA-jh5g-9m4v-9vv9 lists affected ranges: Maven org.apache.karaf.management:org.apache.karaf.management.server >=0 <4.3.6)

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