Report: CVE-2026-33248 - NATS has mTLS verify_and_map authentication bypass via incorrect Subject DN matc
CVE ID :CVE-2026-33248 Published : March 25, 2026, 8:18 p.m. | 40 minutes ago Description :NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, when using mTLS for client identity, with `verify_and_map` to derive a NATS identity from the client certificate's Subject DN, certain patterns of RDN would not be correctly enforced, allowing for authentication bypass. This does require a valid certificate from a CA already trusted for client certificates, and `DN` naming patterns which the NATS maintainers consider highly unlikely. So this is an unlikely attack. Nonetheless, administrators who have been very sophisticated in their `DN` construction patterns might conceivably be impacted. Versions 2.11.15 and 2.12.6 contain a fix. As a workaround, developers should review their CA issuing practices. Severity: 0.0 | NA Visit the link for more details, such as CVSS details, affected products, timeline, and more...