Vulnerability · Published Mar 25, 2026 · Assigned by GitHub_M
CVE-2026-29785NATS Server panic via malicious compression on leafnode port
High 7.5
In plain English
A high-severity null pointer dereference in nats-server from nats-io. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.7% (higher than 53% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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 & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian:12 | nats-server | no fix listed | DEBIAN-CVE-2026-29785 |
| Debian:13 | nats-server | no fix listed | DEBIAN-CVE-2026-29785 |
| Debian:14 | nats-server | 2.12.6-1 | DEBIAN-CVE-2026-29785 |
| Go | github.com/nats-io/nats-server | no fix listed | GO-2026-4829 |
| Go | github.com/nats-io/nats-server | no fix listed | GHSA-52jh-2xxh-pwh6 |
| Go | github.com/nats-io/nats-server/v2 | 2.12.5 | GHSA-52jh-2xxh-pwh6 |
| Go | github.com/nats-io/nats-server/v2 | 2.11.14 | GHSA-52jh-2xxh-pwh6 |
| Go | github.com/nats-io/nats-server/v2 | 2.11.14, 2.12.5 | GO-2026-4829 |
| Ubuntu:24.04:LTS | nats-server | no fix listed | UBUNTU-CVE-2026-29785 |
| Ubuntu:25.10 | nats-server | no fix listed | UBUNTU-CVE-2026-29785 |
| Ubuntu:26.10 | nats-server | no fix listed | UBUNTU-CVE-2026-29785 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| nats-io | nats-server | < 2.11.14>= 2.12.0-RC.1, < 2.12.5 |
Weakness: CWE-476, CWE-409 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
References
- https://github.com/nats-io/nats-server/security/advisories/GHSA-52jh-2xxh-pwh6 x_refsource_CONFIRM
- https://github.com/nats-io/nats-server/commit/a1488de6f2ba6e666aef0f9cce0016f7f167d6a8 x_refsource_MISC
- https://advisories.nats.io/CVE/secnote-2026-04.txt x_refsource_MISC
- https://access.redhat.com/security/cve/CVE-2026-29785 vdb-entry, x_refsource_REDHAT
- RHBZ#2451444 issue-tracking, x_refsource_REDHAT
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-29785.json x_sadp-csaf-vex
- https://access.redhat.com/errata/RHSA-2026:22347 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:23345 vendor-advisory, x_refsource_REDHAT
- https://access.redhat.com/errata/RHSA-2026:21769 vendor-advisory, x_refsource_REDHAT