RabbitMQ CVE-2026-57211

Exploitation requires the target to be running RabbitMQ on Windows (UNC/SMB path semantics do not apply on Linux or macOS) and to have MULTIPLE management extension plugins enabled - the vulnerable rabbit_mgmt_wm_static code path only mishandles the URL-encoded backslash under that plugin arrangement, which is not the default configuration. The attacker must be able to reach the management plugin's HTTP interface (default port 15672) and send a request whose path carries URL-encoded backslashes forming a UNC path to an attacker-controlled host. Limiting factors: Windows-only, non-default plugin configuration, network reachability to the management listener, and attacker-controlled DNS/SMB infrastructure to receive the callback; the realistic payoff is outbound DNS/SMB coercion and NetNTLM credential capture/relay rather than direct code execution.

The signals conflict sharply. The published CVSS 3.1 vector (AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H = 10.0) implies a wormable full-compromise remote flaw, but the description and the 'Information Disclosure' tag describe a much narrower outcome: coerced outbound DNS/SMB to UNC paths, i.e. SSRF and potential NetNTLM hash leakage/relay, not code execution or integrity/availability loss. The C:H/I:H/A:H and Scope:Changed metrics appear inflated relative to the described behavior - verify against the vendor advisory (GHSA-7v84-m3g5-vxq6). EPSS is low (0.28%, 20th percentile), there is no CISA KEV listing, and no public POC, all consistent with lower real-world urgency than the raw 10.0 suggests. Exploitation is further gated by two conditions: the target must run Windows (UNC semantics do not apply on Linux/macOS) and must have multiple management extension plugins enabled, which is not a default posture. Net assessment: a legitimate but conditional issue best treated as elevated rather than emergency priority - patch on an expedited-but-normal cycle, prioritizing internet-exposed Windows management endpoints.

An attacker who can reach the RabbitMQ management HTTP endpoint on a Windows host sends a crafted static-file request whose path contains URL-encoded backslashes pointing to a UNC path such as \\attacker.example.com\share\file. The Windows host resolves the attacker's hostname and opens an SMB connection to it before path validation, leaking a DNS query and the machine's NetNTLM authentication material for capture or relay. No public POC is currently identified, and exploitation requires the non-default multi-extension-plugin configuration.