Bug 2457275 (CVE-2026-39304)

Summary:	CVE-2026-39304 Apache ActiveMQ Client: Apache ActiveMQ Broker: Apache ActiveMQ: Apache ActiveMQ: Denial of Service due to TLSv1.3 KeyUpdate memory exhaustion
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	asoldano, ataylor, bbaranow, bmaxwell, bstansbe, dbruscin, dlofthou, fmariani, gmalinko, gtanzill, istudens, ivassile, iweiss, janstey, jbuscemi, kvanderr, mosmerov, msvehla, nwallace, pberan, pdelbell, pesilva, pjindal, pmackay, rstancel, rstepani, smaestri, tcunning, thjenkin, vdosoudi, yfang
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in Apache ActiveMQ Client, Apache ActiveMQ Broker, and Apache ActiveMQ. A remote attacker can exploit this vulnerability by rapidly triggering Transport Layer Security (TLS) version 1.3 handshake KeyUpdates. This improper handling of KeyUpdates causes the broker to exhaust its memory in the SSL engine, leading to a Denial of Service (DoS) condition where the service becomes unavailable.	Story Points:	---
Clone Of:		Environment:
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oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:
Bug Depends On:	2457420
Bug Blocks:

Description OSIDB Bzimport 2026-04-10 11:01:21 UTC

Denial of Service via Out of Memory vulnerability in Apache ActiveMQ Client, Apache ActiveMQ Broker, Apache ActiveMQ.

ActiveMQ NIO SSL transports do not correctly handle TLSv1.3 handshake KeyUpdates triggered by clients. This makes it possible for a client to rapidly trigger updates which causes the broker to exhaust all its memory in the SSL engine leading to DoS.

Note: TLS versions before TLSv1.3 (such as TLSv1.2) are broken but are not vulnerable to OOM. Previous TLS versions require a full handshake renegotiation which causes a connection to hang but not OOM. This is fixed as well.
This issue affects Apache ActiveMQ Client: before 5.19.4, from 6.0.0 before 6.2.4; Apache ActiveMQ Broker: before 5.19.4, from 6.0.0 before 6.2.4; Apache ActiveMQ: before 5.19.4, from 6.0.0 before 6.2.4.

Users are recommended to upgrade to version 6.2.4 or 5.19.5, which fixes the issue.