NATS-Server Vulnerability in Leafnode Configuration for NATS.io Messaging System
CVE-2026-29785

7.5HIGH

Key Information:

Vendor

Nats-io

Status
Nats-server
Vendor
CVE Published:
25 March 2026

What is CVE-2026-29785?

NATS-Server, designed for high-performance messaging in cloud and edge environments, has a vulnerability that affects users with the 'leafnode' configuration enabled. This configuration, while not default, can allow an unauthenticated remote attacker to crash the server by triggering a panic when compression is enabled. To mitigate this issue, users are advised to disable compression on the leafnode port or upgrade to versions 2.11.14 or 2.12.5, which contain the necessary fixes.

Affected Version(s)

nats-server < 2.11.14 < 2.11.14

nats-server >= 2.12.0-RC.1, < 2.12.5 < 2.12.0-RC.1, 2.12.5

References

https://github.com/nats-io/nats-server/security/advisorie...
x_refsource_CONFIRM
https://github.com/nats-io/nats-server/commit/a1488de6f2b...
x_refsource_MISC
https://advisories.nats.io/CVE/secnote-2026-04.txt
x_refsource_MISC

CVSS V3.1

Score:
7.5
Severity:
HIGH
Confidentiality:
None
Integrity:
None
Availability:
None
Attack Vector:
Network
Attack Complexity:
Low
Privileges Required:
None
User Interaction:
None
Scope:
Unchanged

Timeline

  • Vulnerability published

  • Vulnerability Reserved

.