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CVE-2026-39304

Apache ActiveMQ Client, Apache ActiveMQ Broker, Apache ActiveMQ All, Apache ActiveMQ: Incorrect handling of TLSv1.3 KeyUpdate can be exploited to cause DoS via OOM

Published: Apr 10, 2026Updated: May 1, 2026 Sources: CVE List NVDCWE-400
NVD MITRE
7.5CVSSHIGH
EPSS Score
0.7%
Top 52.4%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
Patch Available

Description

Denial of Service via Out of Memory vulnerability in Apache ActiveMQ Client, Apache ActiveMQ Broker, Apache ActiveMQ. ActiveMQ NIO SSL transports do not correctly handle TLSv1.3 handshake KeyUpdates triggered by clients. This makes it possible for a client to rapidly trigger updates which causes the broker to exhaust all its memory in the SSL engine leading to DoS. Note: TLS versions before TLSv1.3 (such as TLSv1.2) are broken but are not vulnerable to OOM. Previous TLS versions require a full handshake renegotiation which causes a connection to hang but not OOM. This is fixed as well. This issue affects Apache ActiveMQ Client: before 5.19.4, from 6.0.0 before 6.2.4; Apache ActiveMQ Broker: before 5.19.4, from 6.0.0 before 6.2.4; Apache ActiveMQ: before 5.19.4, from 6.0.0 before 6.2.4. Users are recommended to upgrade to version 6.2.4 or 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
Open in CVSS calculator →

Weaknesses

CWE-400

Affected Products

activemqapache
LibraryLibrary
OSS Libraries / generic-library
activemq brokerapache
Mixed
Web & CMS Plugins / cms-core
Apache ActiveMQ ClientApache Software Foundation
Mixed
Web & CMS Plugins / cms-core
Apache ActiveMQ BrokerApache Software Foundation
Mixed
Web & CMS Plugins / cms-core
Apache ActiveMQ AllApache Software Foundation
Mixed
Web & CMS Plugins / cms-core
apacheoss-projectUSWeb & CMS Pluginsaka apache http server, apache httpd
apache software foundationoss-projectUSWeb & CMS Pluginsaka apache foundation
and 1 more affected products View all →

Attack Graph

Products CVE Techniques Tactics

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Exploitability

Official Patch Available

MITRE ATT&CK

1 technique
Impact
View detailed technique mapping

References

https://activemq.apache.org/security-advisories.data/CVE-2026-39304-announcement.txt
activemq.apache.org
http://www.openwall.com/lists/oss-security/2026/04/09/17
openwall.com

Timeline

Published
Apr 10, 2026
Last Updated
May 1, 2026

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