RabbitMQ CVE-2026-57212

Exploitation requires that the rabbitmq_management plugin is enabled and its HTTP API is reachable by the attacker, and - per CVSS PR:L - that the attacker holds valid low-privilege management API credentials able to POST to the with_decode or direct_request paths. The concrete trigger is a valid JSON request body large enough that its final combined size exceeds the limit while the pre-final-chunk accumulated size still passes the read_complete_body check. Limiting factors that reduce real-world risk: authentication is needed (not unauthenticated), the management plugin must be installed and enabled (it is optional though commonly used), and the management port (default 15672) must be network-reachable from the attacker - deployments that keep it internal-only and enforce a proxy body-size limit materially blunt the attack. No user interaction is required (UI:N).

This is a moderate, availability-only risk rather than a top-tier emergency. The vendor CVSS 4.0 vector (AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:L, base 7.1) indicates a network-reachable, low-complexity attack requiring some authentication (PR:L) with high impact only to availability and a limited subsequent-system availability effect (SA:L); confidentiality and integrity are untouched. No EPSS score was provided, there is no KEV listing, and no POC is referenced - so all three exploitation-likelihood signals are either absent or negative. The realistic priority driver is that the management API is authenticated, so an attacker needs at least valid low-privilege management credentials (or a path to them); this meaningfully limits mass exploitation and makes this more of a hardening/patch-on-cycle item than a drop-everything incident, though internet-exposed management ports raise the urgency considerably.

An attacker holding low-privilege RabbitMQ management credentials (or reaching an exposed, weakly-secured 15672 endpoint) sends a crafted, chunked HTTP request to a with_decode or direct_request endpoint whose final combined JSON body exceeds the intended size limit. Because the size check misses the final chunk, the broker buffers and decodes the oversized payload, spiking memory/CPU and degrading or crashing the node, causing a denial of service. No public POC is referenced, but the low attack complexity (AC:L) makes reliable reproduction likely once the endpoint and credentials are known.