No exploitation reportedFix available

CVE-2021-41766

Q: Is CVE-2021-41766 actively exploited?

Active exploitation of CVE-2021-41766 has not been confirmed. Its EPSS score was 2.0% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

Q: What is the CVSS score for CVE-2021-41766?

CVE-2021-41766 has a CVSS v3 base score of 8.1 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.

No exploitation reported by the sources we read.

Published2022-01-26
Fixed in4.3.6
WeaknessCWE-502

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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).

Timeline

dates in UTC

2022-01-2611:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC

Indicators tagged with this CVE, per day0 indicators over 7 days

Block these indicators

Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-41766?format=txt
CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-41766?format=csv
TAXII collection of exploited CVEs
The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD

Apache karaf

Branch	Affected	Fixed in	Source
4.3	< 4.3.6	4.3.6	NVD

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Update Apache karaf to 4.3.6

Advisories and patches

karaf.apache.orgVendor Advisory

Detection

Nuclei template: none so far
Exploit-DB: no entry
Proof-of-concept repositories: none listed

Sources

NVDCVSS 3.18.1read 2026-10-23
NVDCVSS 2.06.8read 2026-10-23
NVDweakness (CWE)CWE-502read 2026-10-23
FIRST EPSSEPSS score2.0 %2026-10-22

Technical details

CVSS v3 Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Published: 2022-01-26
Last Modified: 2026-06-17
NVD status: Modified

Frequently asked questions

What is CVE-2021-41766?

Is CVE-2021-41766 actively exploited?

Active exploitation of CVE-2021-41766 has not been confirmed. Its EPSS score was 2.0% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-41766?

CVE-2021-41766 has a CVSS v3 base score of 8.1 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.

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