RabbitMQ EUVD-2026-87143

Exploitation requires (1) the Shovel or Federation plugin to be in use on the target node, and (2) an authenticated user holding the policymaker tag, since only that tag can set the auth_mechanism value. These are the exact limiting factors: the Shovel/Federation dependency is not a default deployment, and the policymaker tag is a privileged management role, so the attacker must already be a trusted high-privilege actor rather than an anonymous remote client. Impact is limited to availability (node crash via unbounded atom consumption); no data disclosure or modification occurs.

This is a genuine but sharply gated denial-of-service issue, not a critical priority. The vendor CVSS 4.0 vector (AV:N/AC:L/AT:P/PR:H/UI:N/VC:N/VI:N/VA:H) scores 5.9 (medium) with impact confined to availability (VA:H) and no confidentiality or integrity effect - consistent with the description of Erlang VM atom-table exhaustion (CWE-400) crashing the node. The PR:H metric aligns with the stated requirement that setting auth_mechanism needs the policymaker tag, and AT:P (attack requirement present) reflects the dependency on the Shovel or Federation plugin being in use. No EPSS score, no CISA KEV listing, and no public exploit code are present in the input, so exploitation status is no public exploit identified at time of analysis. The double gating - a privileged (policymaker) actor plus a non-default plugin dependency - means real-world risk is well below what a raw network-vector reading might suggest; the attacker is already a trusted, high-privilege management user. There is no signal conflict in the data: the vector, description, and CWE all agree on a privileged-actor availability-only DoS.

In an environment where the Shovel or Federation plugin is active, an actor holding the policymaker tag sets a large auth_mechanism value containing many colon-delimited tokens; mechanisms/1 calls list_to_atom/1 on each token, permanently consuming Erlang VM atoms until the atom table is exhausted and the node crashes. Because the atoms are never reclaimed, a single sufficiently large request can bring the node down. No public proof-of-concept is identified in the provided data.