CVE-2026-27889

Fixed in a distro release EPSS <1%CVSS 7.5

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.

Published 2026-03-25 · CVE record · OSV

Products: nats-io nats-server, Red Hat Multicluster Global Hub 1.4.5, Red Hat Multicluster Global Hub 1.6.5, Red Hat multicluster global hub 1.5.3, Red Hat OpenShift Container Platform 4

Fixed upstream

Distro releases