CVE-2026-29785
NATS Server panic via malicious compression on leafnode port
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.
INFO
Published Date :
March 25, 2026, 8:16 p.m.
Last Modified :
March 26, 2026, 5:13 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 3.1 | HIGH | [email protected] |
Solution
- Update NATS-Server to version 2.11.14 or 2.12.5.
- Disable compression on the leafnode port if unable to update.
- Ensure leafnode configuration is not enabled unless necessary.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-29785.
| URL | Resource |
|---|---|
| https://advisories.nats.io/CVE/secnote-2026-04.txt | Mitigation Vendor Advisory |
| https://github.com/nats-io/nats-server/commit/a1488de6f2ba6e666aef0f9cce0016f7f167d6a8 | Patch |
| https://github.com/nats-io/nats-server/security/advisories/GHSA-52jh-2xxh-pwh6 | Mitigation Vendor Advisory |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-29785 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-29785
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-29785 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-29785 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
Initial Analysis by [email protected]
Mar. 26, 2026
Action Type Old Value New Value Added CPE Configuration OR *cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:* versions from (including) 2.12.0 up to (excluding) 2.12.5 *cpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:* versions up to (excluding) 2.11.14 Added Reference Type GitHub, Inc.: https://advisories.nats.io/CVE/secnote-2026-04.txt Types: Mitigation, Vendor Advisory Added Reference Type GitHub, Inc.: https://github.com/nats-io/nats-server/commit/a1488de6f2ba6e666aef0f9cce0016f7f167d6a8 Types: Patch Added Reference Type GitHub, Inc.: https://github.com/nats-io/nats-server/security/advisories/GHSA-52jh-2xxh-pwh6 Types: Mitigation, Vendor Advisory -
New CVE Received by [email protected]
Mar. 25, 2026
Action Type Old Value New Value Added 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. Added CVSS V3.1 AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Added CWE CWE-476 Added Reference https://advisories.nats.io/CVE/secnote-2026-04.txt Added Reference https://github.com/nats-io/nats-server/commit/a1488de6f2ba6e666aef0f9cce0016f7f167d6a8 Added Reference https://github.com/nats-io/nats-server/security/advisories/GHSA-52jh-2xxh-pwh6