CVSS 3.1
7.5 highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:HCVE-2026-33218
High (7.5) in linuxfoundation nats-server. EPSS 0.6% chance of exploitation in the next 30 days. Fixed in github.com/nats-io/nats-server/v2 2.11.15, 2.12.6.
NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, a client which can connect to the leafnode port can crash the nats-server with a certain malformed message pre-authentication. Versions 2.11.15 and 2.12.6 contain a fix. As a workaround, disable leafnode support if not needed or restrict network connections to the leafnode port, if plausible without compromising the service offered.
Severity
- EPSS
- 0.6% chance of exploitation in the next 30 days; higher than 50% of CVEs (scores of 2026-10-31)
- CWEs
- CWE-20, CWE-1286
- Published
- Modified
- Record from
- the NVD, synced
Affected
- linuxfoundation:nats-server
Packages (OSV)
| Advisory | Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|---|
| GHSA-vprv-35vv-q339 | Go | github.com/nats-io/nats-server/v2 | <2.11.15 | 2.11.15 |
| GHSA-vprv-35vv-q339 | Go | github.com/nats-io/nats-server/v2 | >=2.12.0-RC.1 <2.12.6 | 2.12.6 |
| GHSA-vprv-35vv-q339 | Go | github.com/nats-io/nats-server | all versions | no fix published |
| GO-2026-4837 | Go | github.com/nats-io/nats-server | all versions | no fix published |
| GO-2026-4837 | Go | github.com/nats-io/nats-server/v2 | <2.11.15 >=2.12.0-RC.1 <2.12.6 | 2.11.15, 2.12.6 |