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.
Affected products
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| nats-io | nats-server | >= 2.2.0, < 2.11.14, >= 2.12.0, < 2.12.5 | — |
Fixed in Linux distributions
Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | nats-server | 2.12.6-1 | — |
| Debian 13 | nats-server | No fix yet | — |
| Debian 12 | nats-server | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu 26.10 | nats-server | No fix yet | — |
| Ubuntu 25.10 | nats-server | No fix yet | — |
| Ubuntu 24.04 LTS | nats-server | No fix yet | — |
Show 1 more (older releases, extended support, other products)Fewer releases
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Ubuntu Pro 26.04 LTS | nats-server | No fix yet | — |
openSUSE
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| openSUSE Leap 16.0 | govulncheck-vulndb | 0.0.20260723T184607-160000.1.1 | openSUSE-SU-2026:21483-1 |
| openSUSE Leap 15.6 | govulncheck-vulndb | 0.0.20260326T203309-150000.1.155.2 | SUSE-SU-2026:1135-1 |
Wolfi
| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Wolfi rolling | k3s-1.32 +1 | 1.32.13.1-r5 | — |
Affected packages
| Ecosystem | Package | Affected | Fixed | Record |
|---|---|---|---|---|
| Go | github.com/nats-io/nats-server | all versions | — | GHSA-pq2q-rcw4-3hr6 |
| Go | github.com/nats-io/nats-server/v2 | >= 2.2.0, < 2.11.14 | 2.11.14 | GHSA-pq2q-rcw4-3hr6 |
| Go | github.com/nats-io/nats-server/v2 | >= 2.12.0, < 2.12.5 | 2.12.5 | GHSA-pq2q-rcw4-3hr6 |
| Go | github.com/nats-io/nats-server/v2 | >= 2.2.0, < 2.11.14 · >= 2.12.0, < 2.12.5 | 2.11.14, 2.12.5 | GO-2026-4841 |
Advisories 3
- openSUSE-SU-2026:21483-1 Security update for govulncheck-vulndb SUSE / openSUSE Security Updates · Jul 31, 2026
- WID-SEC-2026-0641 NATS Server: Mehrere Schwachstellen ermöglichen Denial of Service BSI CERT-Bund (WID) · Jun 1, 2026
- SUSE-SU-2026:1135-1 Security update for govulncheck-vulndb SUSE / openSUSE Security Updates · Mar 31, 2026