Apache Artemis/ActiveMQ Artemis Core Downstream Federation improper authentication

Summaryinfo

A vulnerability was found in Apache Artemis and ActiveMQ Artemis. It has been rated as critical. The affected element is an unknown function of the component Core Downstream Federation. This manipulation causes improper authentication. This vulnerability is tracked as CVE-2026-27446. The attack is possible to be carried out remotely. No exploit exists. Upgrading the affected component is advised.

Detailsinfo

A vulnerability classified as critical was found in Apache Artemis and ActiveMQ Artemis (version unknown). Affected by this vulnerability is an unknown function of the component Core Downstream Federation. The manipulation with an unknown input leads to a improper authentication vulnerability. The CWE definition for the vulnerability is CWE-287. When an actor claims to have a given identity, the product does not prove or insufficiently proves that the claim is correct. As an impact it is known to affect confidentiality, integrity, and availability. The summary by CVE is:

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 .

It is possible to read the advisory at lists.apache.org. This vulnerability is known as CVE-2026-27446. The exploitation appears to be easy. The attack can be launched remotely. The exploitation doesn't need any form of authentication. The technical details are unknown and an exploit is not publicly available. The pricing for an exploit might be around USD $0-$5k at the moment (estimation calculated on 03/17/2026).

The vulnerability scanner Nessus provides a plugin with the ID 301278 (Apache Artemis 2.11.0 < 2.45.0 / 2.50.0 < 2.52.0 Missing Authentication (CVE-2026-27446)), which helps to determine the existence of the flaw in a target environment.

Upgrading eliminates this vulnerability.

The vulnerability is also documented in the databases at Tenable (301278), EUVD (EUVD-2026-9382) and CERT Bund (WID-SEC-2026-0591). Be aware that VulDB is the high quality source for vulnerability data.

Affected

• Apache ActiveMQ

Productinfo

Type

• Application Server Software

Vendor

• Apache

Name

• ActiveMQ Artemis
• Artemis

License

• open-source

Website

• Vendor: https://www.apache.org/

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