CVE-2026-27446 Apache Artemis, Apache ActiveMQ Artemis: Auth bypass for Core downstream federation

Critical 9.3 Published 4 Mar 2026 Updated 18 Sep 2026

Unauthenticated attackers can force broker federation to exfiltrate or inject messages if Core protocol connections are allowed from untrusted sources.

Exploited in the wild: Not known
Login needed: Not needed
Attackable: Over the internet
Victim action needed: Not needed
Fix: Available

What is CVE-2026-27446?

CVE-2026-27446 is a critical authentication bypass vulnerability in Apache ActiveMQ Artemis, published on 4 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Missing Authentication for Critical Function (CWE-306) vulnerability in Apache Artemis, Apache ActiveMQ Artemis. An unauthenticated remote attacker can use the Core protocol to force a target broker to establish an outbound Core federation connection to an attacker-controlled rogue broker. This could potentially result in message injection into any queue and/or message exfiltration from any queue via the rogue broker. This impacts environments that allow both:

- incoming Core protocol connections from untrusted sources to the broker

- outgoing Core protocol connections from the broker to untrusted targets

This issue affects:

- Apache Artemis from 2.50.0 through 2.51.0

- Apache ActiveMQ Artemis from 2.11.0 through 2.44.0.

Users are recommended to upgrade to Apache Artemis version 2.52.0, which fixes the issue.

The issue can be mitigated by one of the following:

- Remove Core protocol support from any acceptor receiving connections from untrusted sources. Incoming Core protocol connections are supported by default via the "artemis" acceptor listening on port 61616. See the "protocols" URL parameter configured for the acceptor. An acceptor URL without this parameter supports all protocols by default, including Core.

- Use two-way SSL (i.e. certificate-based authentication) in order to force every client to present the proper SSL certificate when establishing a connection before any message protocol handshake is attempted. This will prevent unauthenticated exploitation of this vulnerability.

- Implement and deploy a Core interceptor to deny all Core downstream federation connect packets. Such packets have a type of (int) -16 or (byte) 0xfffffff0. Documentation for interceptors is available at https://artemis.apache.org/components/artemis/documentation/latest/intercepting-operations.html .

Weakness: CWE-306

Which versions are affected by CVE-2026-27446?

4 open source packages ship an affected version, including org.apache.activemq:artemis-server and org.apache.artemis:artemis-server. It affects 1 product.

Package	Affected	Fixed in
`org.apache.activemq:artemis-server` Maven	From `2.11.0` to `2.44.0`	None
`org.apache.activemq:artemis-server` Maven	From `2.11.0` to `2.44.0`	None
`org.apache.artemis:artemis-server` Maven	From `2.50.0`	`2.52.0`
`org.apache.artemis:artemis-server` Maven	From `2.50.0`	`2.52.0`

Products include Apache Artemis.

How do I fix CVE-2026-27446?

Upgrade to a fixed version.

Upgrade, and rotate credentials and sessions that may have been exposed. More about Authentication bypass.

Is CVE-2026-27446 being exploited?

There is no known exploitation of CVE-2026-27446 in the wild and no public exploit code.

Sources

Also known as CLSA-2026-1782176242, ECHO-2eda-feb8-1153, GHSA-fw88-pf9m-p947, ROOT-APP-MAVEN-CVE-2026-27446, UBUNTU-CVE-2026-27446.