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CVE-2026-40046

Apache ActiveMQ, Apache ActiveMQ All, Apache ActiveMQ MQTT: Missing fix for CVE-2025-66168: MQTT control packet remaining length field is not properly validated

Published: Apr 9, 2026Updated: Apr 13, 2026 Sources: CVE List NVDCWE-190
NVD MITRE
7.5CVSSHIGH
EPSS Score
0.4%
Top 70.9%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available

Description

Integer Overflow or Wraparound vulnerability in Apache ActiveMQ, Apache ActiveMQ All, Apache ActiveMQ MQTT. The fix for "CVE-2025-66168: MQTT control packet remaining length field is not properly validated" was only applied to 5.19.2 (and future 5.19.x) releases but was missed for all 6.0.0+ versions. This issue affects Apache ActiveMQ: from 6.0.0 before 6.2.4; Apache ActiveMQ All: from 6.0.0 before 6.2.4; Apache ActiveMQ MQTT: from 6.0.0 before 6.2.4. Users are recommended to upgrade to version 6.2.4 or a 5.19.x version starting with 5.19.2 or later (currently latest is 5.19.5), which fixes the issue.

CVSS Vector Breakdown

AV:NAC:LPR:NUI:NS:UC:NI:NA:H
Exploitability
AV:NAttack Vector
Network
AC:LAttack Complexity
Low
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:NIntegrity
None
A:HAvailability
High
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Weaknesses

CWE-190

Affected Products

Apache ActiveMQApache Software FoundationDatabases / cache-message-queue
Apache ActiveMQ AllApache Software Foundation
Mixed
Web & CMS Plugins / cms-core
Apache ActiveMQ MQTTApache Software Foundation
Mixed
Web & CMS Plugins / cms-core
apache software foundationoss-projectUSWeb & CMS Pluginsaka apache foundation

Attack Graph

Products CVE Techniques Tactics

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Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

MITRE ATT&CK

1 technique
Initial Access
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References

https://www.cve.org/CVERecord?id=CVE-2025-66168
cve.org
https://activemq.apache.org/security-advisories.data/CVE-2026-40046-announcement.txt
activemq.apache.org
https://lists.apache.org/thread/zdntj5rcgjjzrpow84o339lzldy68zrg
lists.apache.org

Timeline

Published
Apr 9, 2026
Last Updated
Apr 13, 2026

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