---
id: CVE-2026-29785
title: >-
  NATS-Server is a High-Performance server for NATS.io, a cloud and edge native
  messaging system
summary: >-
  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 …
severity: high
cvss: 7.5
cvssVector: 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'
cwe:
  - CWE-476
  - CWE-409
vendor: linuxfoundation
product: nats-server
affected:
  - nats-server < 2.11.14
  - 'nats-server >= 2.12.0, < 2.12.5'
patched:
  - nats-server 2.12.5
published: '2026-03-25'
updated: '2026-09-09'
sourceUpdated: '2026-09-09T13:19:11.863'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-29785'
references:
  - url: 'https://advisories.nats.io/CVE/secnote-2026-04.txt'
    label: security-advisories@github.com
  - url: >-
      https://github.com/nats-io/nats-server/commit/a1488de6f2ba6e666aef0f9cce0016f7f167d6a8
    label: security-advisories@github.com
  - url: >-
      https://github.com/nats-io/nats-server/security/advisories/GHSA-52jh-2xxh-pwh6
    label: security-advisories@github.com
  - url: 'https://access.redhat.com/errata/RHSA-2026:21769'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:22347'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/errata/RHSA-2026:23345'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://access.redhat.com/security/cve/CVE-2026-29785'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://bugzilla.redhat.com/show_bug.cgi?id=2451444'
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: >-
      https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-29785.json
    label: 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
  - url: 'https://www.cve.org/CVERecord?id=CVE-2026-29785'
  - url: 'https://nvd.nist.gov/vuln/detail/CVE-2026-29785'
  - url: 'https://github.com/nats-io/nats-server'
tags:
  - nvd
  - cve.org
  - csaf
  - vex
  - red-hat
  - osv
  - go
ssvc:
  exploitation: none
  automatable: 'yes'
  technicalImpact: partial
  timestamp: '2026-03-28T01:33:48.548539Z'
epss: 0.00658
epssPercentile: 0.49719
ingestedAt: '2026-07-20T12:38:40.646Z'
aliases:
  - GHSA-52jh-2xxh-pwh6
  - BIT-nats-2026-29785
  - GO-2026-4829
ecosystem: go
---

## Overview

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.

## Affected

- `nats-server < 2.11.14`
- `nats-server >= 2.12.0, < 2.12.5`

## Remediation

Upgrade past the affected range:

- `nats-server 2.12.5`

## Vendor advisories

- **RHSA-2026:22347** · Red Hat · fixed in: Multicluster Global Hub 1.4.5 · released 2026-06-01 · [advisory](https://access.redhat.com/errata/RHSA-2026:22347)
- **RHSA-2026:23345** · Red Hat · fixed in: Multicluster Global Hub 1.6.5 · released 2026-06-04 · [advisory](https://access.redhat.com/errata/RHSA-2026:23345)
- **RHSA-2026:21769** · Red Hat · fixed in: Red Hat multicluster global hub 1.5.3 · released 2026-05-28 · [advisory](https://access.redhat.com/errata/RHSA-2026:21769)

## Package advisory (CVE-2026-29785)

Affected packages:

- `github.com/nats-io/nats-server/v2 < 2.11.14`
- `github.com/nats-io/nats-server/v2 >= 2.12.0-RC.1, < 2.12.5`
- `github.com/nats-io/nats-server`

Patched in:

- `github.com/nats-io/nats-server/v2 2.11.14`
- `github.com/nats-io/nats-server/v2 2.12.5`

Source: https://osv.dev/vulnerability/GHSA-52jh-2xxh-pwh6