CVE-2026-59878
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.
No public exploitation has been reported so far. No distribution fix is listed yet; apply vendor mitigations and monitor.
Recommended action: Track your distribution's security tracker and apply the fix as soon as it ships.
Severity metrics
CVSS 3.1 : 7.5 HIGH
Vector: AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Affected & fixed versions by distribution
Versions are the native distribution strings (backport-aware): RHEL/Debian/SUSE backport fixes, so compare with the distro version comparator (dpkg / rpm / vercmp), not the upstream version.
No affected package in the tracked watchlist yet (Debian, Ubuntu, Arch, SUSE, Red Hat...). Triage may still be pending.