PT-2026-31892 · Apache · Apache Activemq+3

Published 2026-04-10 · Updated 2026-04-10 · CVE-2026-39304

NVD

CVSS v3.1

7.5

High

AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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.

Fix

Resource Exhaustion

Weakness Enumeration

CWE-400

Related Identifiers

CVE-2026-39304

Affected Products

Apache Activemq

Apache Activemq Apollo

Apache Activemq Broker

Apache Activemq Client

References · 4

• https://activemq.apache.org/security-advisories.data/CVE-2026-39304-announcement.txt · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-39304 · Security Note
• https://twitter.com/oss_security/status/2042430453043384692 · Twitter Post
• http://openwall.com/lists/oss-security/2026/04/09/17 · Note