High

Apache ActiveMQ: Denial of Service via Out of Memory vulnerability

  • Disclosed: 10.04.2026
  • Updated: 11.10.2026 13:20

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

Click a technology to see all vulnerabilities affecting it.

PlatformPackageVulnerable versionsFixed in
Java / Kotlin (Maven) org.apache.activemq:activemq-all < 5.19.4, >= 6.0.0, < 6.2.4 5.19.4, 6.2.4
Java / Kotlin (Maven) org.apache.activemq:activemq-broker < 5.19.4, >= 6.0.0, < 6.2.4 5.19.4, 6.2.4
Java / Kotlin (Maven) org.apache.activemq:activemq-client < 5.19.4, >= 6.0.0, < 6.2.4 5.19.4, 6.2.4
Java / Kotlin (Maven) org.apache.activemq:apache-activemq < 5.19.4, >= 6.0.0, < 6.2.4 5.19.4, 6.2.4

References

CVSS score 7.5/10
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Weakness (CWE)
CWE-400
Platform
Java / Kotlin (Maven)
Package
org.apache.activemq:activemq-all, org.apache.activemq:activemq-broker, org.apache.activemq:activemq-client
Disclosed
10.04.2026
Updated
11.10.2026 13:20

Sources and licenses

OSV / GitHub Advisory Database - GHSA-5568-6qcg-g7fx - CC BY 4.0

Vulnerability history: org.apache.activemq:activemq-broker

All published vulnerabilities of this package (Java / Kotlin (Maven)), newest first. Shows whether this is a one-off slip or a package that needs watching.

All (12) in the archive
Total entries
12
First → latest
05.2022 06.2026
Without a fix
0
Exploited in attacks
1

Severity breakdown

  • Critical 1
  • High 7
  • Medium 4

Disclosures per year

  1. 2022: 3
  2. 2023: 0
  3. 2024: 0
  4. 2025: 0
  5. 2026: 9
Severity:
  1. High · 8.8 CVE-2026-45505 < 5.19.7, >= 6.0.0, < 6.2.6 5.19.7, 6.2.6
  2. High · 8.1 CVE-2026-42588 < 5.19.7, >= 6.0.0, < 6.2.6 5.19.7, 6.2.6
  3. High · 8.8 CVE-2026-40466 < 5.19.6, >= 6.0.0, < 6.2.5 5.19.6, 6.2.5
  4. High · 8.8 CVE-2026-41044 < 5.19.6, >= 6.0.0, < 6.2.5 5.19.6, 6.2.5
  5. Apache ActiveMQ: Denial of Service via Out of Memory vulnerability this entry
    High · 7.5 CVE-2026-39304 < 5.19.4, >= 6.0.0, < 6.2.4 5.19.4, 6.2.4
  6. High · 8.8 Exploited in attacks CVE-2026-34197 < 5.19.5, >= 6.0.0, < 6.2.3 5.19.5, 6.2.3
  7. High CVE-2014-3612 >= 5.0.0, < 5.10.1 5.10.1
  8. Critical · 9.8 CVE-2014-3600 >= 5.0.0, < 5.10.1 5.10.1

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