EUVD-2026-21362
GHSA-5568-6qcg-g7fx
CVSS Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Lifecycle Timeline
4Tags
Description
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.
Analysis
Out-of-memory denial of service in Apache ActiveMQ allows unauthenticated remote attackers to exhaust broker memory via rapid TLSv1.3 KeyUpdate requests. Affects ActiveMQ Client, Broker, and All distributions versions <5.19.4 and 6.0.0-6.2.3 when NIO SSL transports are used. …
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Remediation
Within 24 hours: Identify all ActiveMQ deployments using versions <5.19.4 or 6.0.0-6.2.3 with NIO SSL transports enabled and assess business criticality. Within 7 days: Implement network-level controls (rate limiting, connection throttling on TLSv1.3 KeyUpdate requests) or disable NIO SSL transport if operationally feasible; apply compensating controls below. …
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