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 products
linuxfoundation: nats-server
References9
- advisories.nats.io/CVE/secnote-2026-04.txt MitigationVendor Advisory
- github.com/nats-io/nats-server/security/advisories/GHSA-52jh-2x… MitigationVendor Advisory
- github.com/nats-io/nats-server/commit/a1488de6f2ba6e666aef0f9cc… Patch
- access.redhat.com/errata/RHSA-2026:21769
- access.redhat.com/errata/RHSA-2026:22347
- access.redhat.com/errata/RHSA-2026:23345
- access.redhat.com/security/cve/CVE-2026-29785
- bugzilla.redhat.com/show_bug.cgi?id=2451444
- security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-29785…
Metrics
- CVSS 3.1
-
7.5
HIGH
Score source: CNA
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H - EPSS — exploit probability
- 1% percentile: 54 · as of 12 November 2026
- CWE
- CWE-476CWE-409
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