Description
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.
Affected products
linuxfoundation: nats-server
References8
- advisories.nats.io/CVE/secnote-2026-10.txt MitigationVendor Advisory
- github.com/nats-io/nats-server/security/advisories/GHSA-vprv-35… MitigationVendor Advisory
- access.redhat.com/errata/RHSA-2026:21769
- access.redhat.com/errata/RHSA-2026:22347
- access.redhat.com/errata/RHSA-2026:23345
- access.redhat.com/security/cve/CVE-2026-33218
- bugzilla.redhat.com/show_bug.cgi?id=2451450
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-33218…
Metrics
- CVSS 3.1
-
7.5
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS — exploit probability
- 1% percentile: 51 · as of 12 November 2026
- CWE
- CWE-20CWE-1286
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