VULNERABILITY INTELLIGENCE

CVE-2026-27889

CVSS score7.5 HIGH
EPSS probability0.59%
CISA KEVNot currently listed
Published2026-03-25
Last modified2026-09-09
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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.

Weakness classification

  • security-advisories@github.com: CWE-190
  • 0b0ca135-0b70-47e7-9f44-1890c2a1c46c: CWE-1286

Primary references