CVE-2026-50734

A flaw was found in Apache ActiveMQ. An unauthenticated network attacker can exploit this vulnerability by sending a specially crafted WireFormatInfo frame with an excessively large size value. This unvalidated value causes the broker to attempt an oversized memory allocation during pre-authentication negotiation. Consequently, this can lead to an Out Of Memory (OOM) error, resulting in a Denial of Service (DoS) and crashing the broker.

A flaw was found in Apache ActiveMQ Classic's OpenWire protocol handling. An unauthenticated remote attacker can crash the broker by sending a crafted WireFormatInfo frame with a malicious oversized value during pre-authentication protocol negotiation, causing an Out of Memory condition. Red Hat AMQ Broker is based on Apache ActiveMQ Artemis, but its OpenWire protocol support delegates wire format negotiation to Classic ActiveMQ's activemq-client code, which is vulnerable to this attack on the OpenWire listener port.

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.