CVE-2026-59878: Apache ActiveMQ AMQP, Apache ActiveMQ, Apache ActiveMQ All: AMQP NIO negative frame size validation bypass leading to DoS

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.8% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-07-28 · updated 2026-08-05
Weakness: CWE-20

Description

Improper Input Validation vulnerability in Apache ActiveMQ AMQP, Apache ActiveMQ, Apache ActiveMQ All. A remote unauthenticated peer that can reach an exposed AMQP NIO connector can trigger denial-of-service behavior by sending a frame size value. This cause the NIO threads to die and if done rapidly enough can lead to exhaustion of the NIO thread pool denying service to other connections. This issue affects Apache ActiveMQ AMQP: before 5.19.9, from 6.0.0 before 6.2.8; Apache ActiveMQ: before 5.19.9, from 6.0.0 before 6.2.8; Apache ActiveMQ All: before 5.19.9, from 6.0.0 before 6.2.8. Users are recommended to upgrade to version 5.19.9, 6.2.8, or 6.3.0 which fixes the issue.

Affected products

Apache ActiveMQ: before 5.19.9; from 6.0.0 before 6.2.8 — fixed in 5.19.9, 6.2.8
Apache Activemq All: before 5.19.9; from 6.0.0 before 6.2.8 — fixed in 5.19.9, 6.2.8
Apache Activemq Amqp: before 5.19.9; from 6.0.0 before 6.2.8 — fixed in 5.19.9, 6.2.8

How to fix

Upgrade to a fixed version: Apache ActiveMQ 5.19.9, 6.2.8; Apache Activemq All 5.19.9, 6.2.8; Apache Activemq Amqp 5.19.9, 6.2.8. Check the vendor advisory for mitigations.

References

Get alerted when CVE-2026-59878 or the next vulnerability affects your stack