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.

There are packages installed that are affected by a vulnerability referenced in the following CVE:

  - 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-2026-27889)

An update of the telegraf package has been released.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - 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-2026-27889)

Note that Nessus relies on the presence of the package as reported by the vendor.

ID	Name	Product	Family	Type	Severity
464194	Echo: github.com/nats-io/nats-server/v2: security update to 2.11.14	Tenable Cloud Security	Echo Local Security Checks	Local	high
464194	Echo: github.com/nats-io/nats-server/v2: security update to 2.11.14	Tenable Self-Hosted Container Security	Echo Local Security Checks	Local	high
332435	Photon OS 5.0: Telegraf PHSA-2026-5.0-91-0841	Nessus	PhotonOS Local Security Checks	Local	high
312343	Photon OS 5.0: Telegraf PHSA-2026-5.0-0841	Nessus	PhotonOS Local Security Checks	Local	high
303826	Linux Distros Unpatched Vulnerability : CVE-2026-27889	Nessus	Misc.	Local	high

Detections

Analytics

CVE-2026-27889

high

Tenable Plugins

high

high

high

high

high