Bug 2451450 (CVE-2026-33218) - CVE-2026-33218 nats-server: github.com/nats-io/nats-server: NATS-Server: Denial of Service via malformed message pre-authentication on leafnode port
Summary: CVE-2026-33218 nats-server: github.com/nats-io/nats-server: NATS-Server: Deni...
Keywords:
Status: NEW
Alias: CVE-2026-33218
Product: Security Response
Classification: Other
Component: vulnerability
Version: unspecified
Hardware: All
OS: Linux
high
high
Target Milestone: ---
Assignee: Product Security DevOps Team
QA Contact:
URL:
Whiteboard:
Depends On: 2451498
Blocks:
TreeView+ depends on / blocked
 
Reported: 2026-03-25 20:02 UTC by OSIDB Bzimport
Modified: 2026-03-25 21:17 UTC (History)
5 users (show)

Fixed In Version:
Clone Of:
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Description OSIDB Bzimport 2026-03-25 20:02:37 UTC 
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.
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