nats-server: NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system
CVE-2026-33219 is fixed in 2 products on 1 platform, first by DEBIAN-CVE-2026-33219, released March 25, 2026. It is not reported as exploited. Patch Radar priority: Routine.
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 malicious client which can connect to the WebSockets port can cause unbounded memory use in the nats-server before authentication; this requires sending a corresponding amount of data. This is a milder variant of CVE-2026-27571. That earlier issue was a compression bomb, this vulnerability is not. Attacks against this new issue thus require significant client bandwidth. Versions 2.11.15 and 2.12.6 contain a fix. As a workaround, disable websockets if not required for project deployment.
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-2026-33219 | Mar 25, 2026 |
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