Information disclosure via access control bypass in wildcard and queue subscriptions

Summary

NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.14.0, 2.12.7, and 2.11.16, an authenticated user could receive messages on denied subjects when a wildcard subscription overlapped with a configured wildcard deny rule but was not a subset of it, and queue subscriptions could also affect delivery to legitimate queue consumers. This issue is fixed in versions 2.14.0, 2.12.7, and 2.11.16. A flaw was found in NATS Server. This could lead to unauthorized information disclosure. Moderate: An information disclosure flaw in NATS Server allows an authenticated user to bypass configured access restrictions, enabling them to receive messages on subjects that should be denied. This occurs when wildcard subscriptions overlap with deny rules or when queue subscriptions interfere with message delivery. Red Hat severity: Moderate — CVSS 6.5 (CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N). Weakness: CWE-551. Red Hat lists Red Hat Hardened Images as not affected.