CVE WatchJul 15, 2026

CVE-2026-27889

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 versi

CVSS

7.5

High

EPSS

0.6%

p44

KEV

—

Exploit Today

0-100

Published: Mar 25, 2026 · Last modified: Jul 15, 2026 · CWE-190 · CWE-1286

EPSS · 30d

0.6%EPSS · 30 days0.6%

2026-06-302026-07-16

Technical 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.

Official references

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