NATS has mTLS verify_and_map authentication bypass via incorrect Subject DN matching (nats-io nats-server)
At a glance
- Source
- NVD
- EPSS
- EPSS 0.15 % · percentile 4 ()
- State
- PUBLISHED
- Published
- Updated
- Assigner
- GitHub_M
- NVD status
- Analyzed
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.
Weaknesses (CWE)
References
Scores
| Version | Score | Vector | Scored by |
|---|---|---|---|
| CVSS 3.1 | MEDIUM 4.2 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N | GitHub_M |
| CVSS 3.1 | MEDIUM 4.2 | CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N | NVD · security-advisories@github.com (Secondary) |
Advisories
- GHSA-3f24-pcvm-5jqc — NATS has mTLS verify_and_map authentication bypass via incorrect Subject DN matching
- GO-2026-4828 — NATS has mTLS verify_and_map authentication bypass via incorrect Subject DN matching in github.com/nats-io/nats-server
European references
- ENISA EUVD · EUVD-2026-15999
- GCVE · GCVE-0-2026-33248
Affected configurations (NVD CPE)
cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*< 2.11.15cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*≥ 2.12.0 < 2.12.6
Affected products
| Product | Versions |
|---|---|
| nats-io · nats-server | affected < 2.11.15 ; affected >= 2.12.0-RC.1, < 2.12.6 |
Sources
| Source | Licence |
|---|---|
| CVE List (CVEProject cvelistV5) | CVE Program Terms of Use |
| EPSS (FIRST.org) | FIRST — attribution requested |
| ENISA EUVD | ENISA — reproduction authorised, source acknowledged |
| NVD (NIST) via fkie-cad/nvd-json-data-feeds | Public domain — this product uses data from the NVD API but is not endorsed or certified by the NVD |