CVE-2026-33248

MEDIUM EPSS 4.0%
Published Mar 25, 20263mo ago · Modified Jun 17, 20261w ago
4.2 CVSS 3.1
Medium
Find Similar
Published Mar 25, 2026 3mo ago
Last Modified Jun 17, 2026 1w 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.

CVSS Details

Base Score
4.2
Exploitability
1.6
Impact
2.5
Vector string
CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:N
Attack Vector Network
Attack Complexity High
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality Low
Integrity Low
Availability None

Threat Intelligence

EPSS Exploit Probability
4.0% percentile
Exploit & Patch Status
No Known Exploit
No Patch Available

Weaknesses 2

CWE-287 Improper Authentication Authentication
CWE-295

Affected Products 2

VendorProductVersionRange
linuxfoundationnats-server* <2.11.15
linuxfoundationnats-server*≥2.12.0  –  <2.12.6

References 2

  • advisories.nats.io https://advisories.nats.io/CVE/secnote-2026-13.txt
    Vendor Advisory
  • github.com https://github.com/nats-io/nats-server/security/advisories/GHSA-3f24-pcvm-5jqc
    Vendor Advisory

Remediation

No remediation data recorded yet

Check vendor advisories and the NVD entry for patch availability.