CVE-2026-27889

HIGH

7.5

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.

CVE Details

CVSS v3.1 Score7.5

SeverityHIGH

CVSS VectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack VectorNETWORK

ComplexityLOW

Privileges RequiredNONE

User InteractionNONE

Published3/25/2026

Last Modified3/26/2026

Sourcenvd

Honeypot Sightings0

Affected Products

linuxfoundation:nats-server

Weaknesses (CWE)

CWE-190

References

https://advisories.nats.io/CVE/secnote-2026-03.txt(security-advisories@github.com)

https://github.com/nats-io/nats-server/security/advisories/GHSA-pq2q-rcw4-3hr6(security-advisories@github.com)

IOC Correlations

No correlations recorded

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