Description (CNA)
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.
Affected (CNA)
| Vendor / product | Versions |
|---|---|
| nats-io / nats-server | affected >= 2.2.0, < 2.11.14; affected >= 2.12.0, < 2.12.5 |
CWE
CWE-190
References
- https://github.com/nats-io/nats-server/security/advisories/GHSA-pq2q-rcw4-3hr6
- https://advisories.nats.io/CVE/secnote-2026-03.txt
ADP enrichment
No English description supplied.
No references supplied.
A flaw was found in NATS-Server, a high-performance messaging system. A remote attacker can exploit this vulnerability before authentication by sending a specially crafted WebSockets frame. This missing sanity check can trigger a server panic, leading to a Denial of Service (DoS) for affected deployments that use WebSockets and expose the network port to untrusted endpoints.
- https://access.redhat.com/security/cve/CVE-2026-27889
- https://bugzilla.redhat.com/show_bug.cgi?id=2451447
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-27889.json
- https://access.redhat.com/errata/RHSA-2026:22347
- https://access.redhat.com/errata/RHSA-2026:23345
- https://access.redhat.com/errata/RHSA-2026:21769