initial report:
Auth Bypass — Artemis cluster-password leaked to JGroups-spoofed peer → broker MANAGE takeover (JBoss EAP)

Composite authentication bypass: an attacker on the JGroups cluster backplane spoofs a discovery response to join the cluster, and the legitimate Artemis broker transmits its cluster-password in plaintext during the handshake; with this password the attacker authenticates to the CORE cluster channel via :8080 from any network position, gaining full MANAGE-level broker authority including message injection, journal access, and topology manipulation.
findings/jboss-eap_35.md

-----
secarx findings:
  Prerequisites for exploitation:

  1. JGroups network access: The attacker must be on the same multicast-reachable network segment as the JGroups private interface. In default configurations, the
  private interface binds to 127.0.0.1, so the attacker would need the administrator to have changed jboss.bind.address.private to a routable address (which is required
  for actual multi-node clustering to work). In any real HA deployment, this address is set to a routable interface.
  2. Cluster password capture: If the administrator has not set an explicit cluster-password (left as "CHANGE ME!!"), each node generates a different random UUID and
  clustering is broken. In any functioning HA deployment, the administrator has set a shared password. When the legitimate broker initiates a ClusterConnectionBridge to
  the attacker's spoofed node, the CreateSessionMessage containing this shared password is sent in plaintext. The attacker captures it passively.
  3. Port 8080 reachability: The attacker must have TCP access to port 8080 on any cluster member. This port is the standard application HTTP port and is typically
  accessible from client networks.

  Attack flow:

  Step 1 — The attacker responds to JGroups PING/MPING discovery on the cluster backplane, advertising a spoofed broker endpoint. No AUTH is checked.

  Step 2 — A legitimate broker node establishes a ClusterConnectionBridge to the attacker's spoofed endpoint, sending a CreateSessionMessage containing the cluster user
  and password in plaintext. The attacker captures the password.

  Step 3 — From any network position that can reach port 8080, the attacker performs an HTTP upgrade to the CORE protocol (no authentication required for the upgrade
  itself).

  Step 4 — The attacker sends a CreateSessionMessage with username=ACTIVEMQ.CLUSTER.ADMIN.USER and password=the captured value. Artemis SecurityStoreImpl authenticates
  this internally, bypassing Elytron and all RBAC checks.

  Step 5 — The attacker has full MANAGE-level authority: message injection and consumption on all addresses, queue creation and deletion, journal access through
  management operations, and topology manipulation.


There are some major network level pre-requisites and because of that it should be considered as Important but not Critical. Should be filed as a new CVE and trackers should be created as EAP 8.0 and 8.1 are in full support and should fix this CVE.