nats-server: NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system
CVE-2026-27889 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-27889, released March 25, 2026. It is not reported as exploited. Patch Radar priority: High.
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.
Where it's fixed
| Product | Fixed in | Fix | Released |
|---|---|---|---|
| Linux | |||
| govulncheck-vulndb · opensuse-leap 15.6 | 0.0.20260326T203309-150000.1.155.2 | SUSE-SU-2026:1135-1 | Mar 27, 2026 |
| govulncheck-vulndb · opensuse-leap 16.0 | 0.0.20260723T184607-160000.1.1 | OPENSUSE-SU-2026:21483-1 | Jul 30, 2026 |
| nats-server · Debian 14 | 2.12.6-1 | DEBIAN-CVE-2026-27889 | Mar 25, 2026 |
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