CVE-2026-27889

7.5 HIGH
Published: March 25, 2026 Modified: March 26, 2026
View on NVD

Description

NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Starting in version 2.2.0 and prior to versions 2.11.14 and 2.12.5, a missing sanity check on a WebSockets frame could trigger a server panic in the nats-server. This happens before authentication, and so is exposed to anyone who can connect to the websockets port. Versions 2.11.14 and 2.12.5 contains a fix. A workaround is available. The vulnerability only affects deployments which use WebSockets and which expose the network port to untrusted end-points. If one is able to do so, a defense in depth of restricting either of these will mitigate the attack.

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CVSS v3.x Details

0.0 Low Medium High Critical 10.0
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

References to Advisories, Solutions, and Tools

Patch Vendor Advisory Exploit Third Party Advisory
https://advisories.nats.io/CVE/secnote-2026-03.txt
Source: security-advisories@github.com
Mitigation Vendor Advisory
https://github.com/nats-io/nats-server/security/advisories/GHSA-pq2q-rcw4-3hr6
Source: security-advisories@github.com
Mitigation Vendor Advisory

2 reference(s) from NVD

Quick Stats

CVSS v3 Score
7.5 / 10.0
EPSS (Exploit Probability)
0.1%
24th percentile
Exploitation Status
Not in CISA KEV

Weaknesses (CWE)

Affected Vendors

linuxfoundation