CVE-2026-50734: Apache ActiveMQ Client, Apache ActiveMQ, Apache ActiveMQ All: Pre-authentication OpenWire memory-allocation DoS during wire format negotiation

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.7% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-06-30 · updated 2026-07-02
Weakness: CWE-789

Description

Memory Allocation with Excessive Size Value vulnerability in Apache ActiveMQ Client, Apache ActiveMQ, Apache ActiveMQ All. An unauthenticated network attacker can cause a broker DoS by sending a crafted WireFormatInfo frame with a malicious large size value. The value is not validate and causes the broker to attempt allocation during pre-auth negotiation which can trigger OOM and crash the broker. This issue affects Apache ActiveMQ Client: before 5.19.8, from 6.0.0 before 6.2.7; Apache ActiveMQ: before 5.19.8, from 6.0.0 before 6.2.7; Apache ActiveMQ All: before 5.19.8, from 6.0.0 before 6.2.7. Users are recommended to upgrade to version 6.2.7 or 5.19.8, which fixes the issue.

Affected products

Apache ActiveMQ: before 5.19.8; from 6.0.0 before 6.2.7 — fixed in 5.19.8, 6.2.7

How to fix

Upgrade to a fixed version: Apache ActiveMQ 5.19.8, 6.2.7. Check the vendor advisory for mitigations.

References

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