CVE-2026-53917

A flaw was found in Apache ActiveMQ. An authenticated user can exploit this vulnerability by sending a specially crafted OpenWire Message with an excessively large encoded size value for the message property map. This lack of size validation during unmarshaling can lead to an out-of-memory error, causing the broker to crash and resulting in a Denial of Service (DoS).

Red Hat products ship Apache ActiveMQ Classic components as transitive dependencies. The vulnerability is in the OpenWire message property map unmarshalling code in activemq-client, which does not validate encoded size values, allowing an authenticated attacker to trigger OOM. While AMQ Broker (Artemis) delegates OpenWire deserialization to Classic's activemq-client code, this attack requires authentication and has only moderate availability impact.

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 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.