NATS has pre-auth server panic via leafnode handling_CVE-2026-33218

7.5 / 10

HIGH

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

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.

Basic Information

ID CVE-2026-33218

Source GitHub_M

Published Mar 25, 2026 at 19:53

Modified Mar 26, 2026 at 15:37

Affected Product

Vendor nats-io

Product nats-server

Version < < 2.11.15

Affected Versions nats-io nats-server < < 2.11.15
nats-io nats-server >= 2.12.0-RC.1, < 2.12.6

CWE Classification

CWE-20

References

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    "published": "2026-03-25T19:53:12.075Z",
    "modified": "2026-03-26T15:37:59.614Z",
    "type": "cve",
    "title": "NATS has pre-auth server panic via leafnode handling",
    "source": "GitHub_M",
    "references": "https://github.com/nats-io/nats-server/security/advisories/GHSA-vprv-35vv-q339\nhttps://advisories.nats.io/CVE/secnote-2026-10.txt",
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