CVE-2026-29785
HIGH7.5EPSS 0.14%NATS Server panic via malicious compression on leafnode port in github.com/nats-io/nats-server
Published: 3/24/2026Modified: 4/28/2026
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.
Affected packages (6)
- Bitnami/natsfrom 0, < 2.11.14, >= 2.12.0, < 2.12.5
- Debian/nats-serverfrom 0
- Go/github.com/nats-io/nats-serverfrom 0
- Go/github.com/nats-io/nats-serverfrom 0
- Go/github.com/nats-io/nats-server/v2from 0, < 2.11.14
- Go/github.com/nats-io/nats-server/v2from 0, < 2.11.14, >= 2.12.0-RC.1, < 2.12.5
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | HIGH7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
References (6)
- ADVISORYhttps://nvd.nist.gov/vuln/detail/CVE-2026-29785
- ADVISORYhttps://security-tracker.debian.org/tracker/CVE-2026-29785
- PATCHhttps://github.com/nats-io/nats-server
- WEBhttps://advisories.nats.io/CVE/secnote-2026-04.txt
- WEBhttps://github.com/nats-io/nats-server/commit/a1488de6f2ba6e666aef0f9cce0016f7f167d6a8
- WEBhttps://github.com/nats-io/nats-server/security/advisories/GHSA-52jh-2xxh-pwh6