CVE-2026-39304
Apache ActiveMQ Client: Apache ActiveMQ Broker: Apache ActiveMQ: Apache ActiveMQ: Denial of Service due to TLSv1.3 KeyUpdate memory exhaustion
Severity
ImportantRed Hat Product Security
CVSS 3.1
Review impact separately from score.
Published · April 10, 2026
Updated · November 5, 2026
Description
A flaw was found in Apache ActiveMQ Client, Apache ActiveMQ Broker, and Apache ActiveMQ. A remote attacker can exploit this vulnerability by rapidly triggering Transport Layer Security (TLS) version 1.3 handshake KeyUpdates. This improper handling of KeyUpdates causes the broker to exhaust its memory in the SSL engine, leading to a Denial of Service (DoS) condition where the service becomes unavailable.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
CVSS / CWE
CVSS 3.1 · 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CWE-770 · Allocation of Resources Without Limits or Throttling