CVE-2026-29785

Description

NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.14 and 2.12.5, if the nats-server has the "leafnode" configuration enabled (not default), then anyone who can connect can crash the nats-server by triggering a panic. This happens pre-authentication and requires that compression be enabled (which it is, by default, when leafnodes are used). Versions 2.11.14 and 2.12.5 contain a fix. As a workaround, disable compression on the leafnode port.

How to fix CVE-2026-29785

To remediate CVE-2026-29785, upgrade the affected package to a fixed version below.

• —upgrade to 2.11.14 or later
• —no fix listed
• —no fix listed
• —no fix listed
• —upgrade to 2.11.14 or later
• —upgrade to 2.11.14 or later

Is CVE-2026-29785 being exploited?

Low — EPSS is 0.1%, meaning exploitation activity has not been observed at scale.

Affected packages (6)

• from 0, < 2.11.14, >= 2.12.0, < 2.12.5
• from 0
• from 0
• from 0
• from 0, < 2.11.14
• from 0, < 2.11.14, >= 2.12.0-RC.1, < 2.12.5

CVSS scores

References (6)

• ADVISORYnvd.nist.gov/vuln/detail/CVE-2026-29785
• ADVISORYsecurity-tracker.debian.org/tracker/CVE-2026-29785
• PATCHgithub.com/nats-io/nats-server
• WEBadvisories.nats.io/CVE/secnote-2026-04.txt
• WEB