Vulnerability in Linuxfoundation Nats-Server
CVE-2026-58208
NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.14.3 and 2.12.12, a WebSocket listener could route requests for the MQTT-over-WebSocket path into MQTT handling even when MQTT was not configured, allowing an unauthenticated client with access to the WebSocket listener to reach uninitialized MQTT state and crash the server process. This issue is fixed in versions 2.14.3 and 2.12.12.
Published · last modified .
CVSS v3 metric
CVSS v3 base score 6.8 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.006 (47.1th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 47th percentile — 47.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.006 · change: 0.000
Affected products
- Linuxfoundation Nats-Server
- Nats-Io Nats-Server — versions >= 2.14.0-RC.1, < 2.14.3, < 2.12.12
Weakness classification (CWE)
References
- github.com/nats-io/nats-server/security/advisories/GHSA-p957-7v2w-g93g (Mitigation, Vendor Advisory)
- github.com/nats-io/nats-server/commit/73b3dd9a5ea0fa7bf08b702338676355b29b5fb4 (Patch)
- github.com/nats-io/nats-server/commit/837536b98b3a9280b993282155ff2bdd3ca38c30 (Patch)
- github.com/nats-io/nats-server/releases/tag/v2.12.12 (Release Notes)
- github.com/nats-io/nats-server/releases/tag/v2.14.3 (Release Notes)
Frequently asked questions
- What is CVE-2026-58208?
- CVE-2026-58208 is a medium-severity vulnerability in Linuxfoundation Nats-Server, classified under CWE-248. CVSS score: 6.8/10. Published 2026-07-08.
- How severe is CVE-2026-58208?
- Medium severity. CVSS v3 base score is 6.8 out of 10.