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 9, 2026
·
Updated

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.

Affected Software

14 affected componentsFixes available
maven/org.apache.activemq:apache-activemq>=6.0.0<6.2.4
6.2.4
maven/org.apache.activemq:apache-activemq<5.19.4
5.19.4
maven/org.apache.activemq:activemq-all>=6.0.0<6.2.4
6.2.4
maven/org.apache.activemq:activemq-all<5.19.4
5.19.4
maven/org.apache.activemq:activemq-broker>=6.0.0<6.2.4
6.2.4
maven/org.apache.activemq:activemq-broker<5.19.4
5.19.4
maven/org.apache.activemq:activemq-client>=6.0.0<6.2.4
6.2.4
maven/org.apache.activemq:activemq-client<5.19.4
5.19.4
Apache ActiveMQ<5.19.4
Apache ActiveMQ>=6.0.0<6.2.4
Apache ActiveMQ Broker<5.19.4
Apache ActiveMQ Broker>=6.0.0<6.2.4
IBM Engineering Requirements Management DOORS and DOORS Web Access<=9.7.2.1 - 9.7.2.11
IBM Engineering Requirements Management DOORS and DOORS Web Access<=9.6.1.1 - 9.6.1.13

Remediation

Recommended actions to resolve this vulnerability, in priority order.

  1. Upgrade

    Upgrade maven/org.apache.activemq:apache-activemq to a version that resolves this vulnerability.

    Fixed in 6.2.4
  2. Upgrade

    Upgrade maven/org.apache.activemq:apache-activemq to a version that resolves this vulnerability.

    Fixed in 5.19.4
  3. Upgrade

    Upgrade maven/org.apache.activemq:activemq-all to a version that resolves this vulnerability.

    Fixed in 6.2.4
  4. Upgrade

    Upgrade maven/org.apache.activemq:activemq-all to a version that resolves this vulnerability.

    Fixed in 5.19.4
  5. Upgrade

    Upgrade maven/org.apache.activemq:activemq-broker to a version that resolves this vulnerability.

    Fixed in 6.2.4
  6. Upgrade

    Upgrade maven/org.apache.activemq:activemq-broker to a version that resolves this vulnerability.

    Fixed in 5.19.4
  7. Upgrade

    Upgrade maven/org.apache.activemq:activemq-client to a version that resolves this vulnerability.

    Fixed in 6.2.4
  8. Upgrade

    Upgrade maven/org.apache.activemq:activemq-client to a version that resolves this vulnerability.

    Fixed in 5.19.4
  9. Upgrade

    Upgrade Apache ActiveMQ Client, Apache ActiveMQ Broker, Apache ActiveMQ All to a version that resolves this vulnerability.

    Fixed in 6.2.4
  10. Upgrade

    Upgrade Apache ActiveMQ Client, Apache ActiveMQ Broker, Apache ActiveMQ All to a version that resolves this vulnerability.

    Fixed in 5.19.5

Event History

Apr 10, 2026
CVE Published
via MITRE·10:54 AM
Data Sourced
via MITRE·10:54 AM
DescriptionWeakness
Data Sourced
via Red Hat·11:01 AM
DescriptionSeverityAffected Software
Data Sourced
via NVD·11:16 AM
DescriptionSeverityWeakness
Data Sourced
via NVD·11:16 AM
Affected Software
Advisory Published
via GitHub·12:31 PM
Data Sourced
via GitHub·12:31 PM
DescriptionSeverityWeaknessAffected Software
Jul 6, 2026
Data Sourced
via IBM·12:00 AM
DescriptionAffected Software

Parent advisories

This vulnerability appears in the following advisories.

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