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.
Weakness
The product dereferences a pointer that it expects to be valid but is NULL.
Affected Software
| Name | Vendor | Start Version | End Version |
|---|---|---|---|
| Nats-server | Linuxfoundation | * | 2.11.14 (excluding) |
| Nats-server | Linuxfoundation | 2.12.0 (including) | 2.12.5 (excluding) |
| Multicluster Global Hub 1.4.5 | RedHat | multicluster-globalhub/multicluster-globalhub-grafana-rhel9:1779579439 | * |
| Multicluster Global Hub 1.5.4 | RedHat | multicluster-globalhub/multicluster-globalhub-grafana-rhel9:1778867753 | * |
| Multicluster Global Hub 1.6.2 | RedHat | multicluster-globalhub/multicluster-globalhub-grafana-rhel9:1780167118 | * |
| Nats-server | Ubuntu | questing | * |
Potential Mitigations
References
- https://advisories.nats.io/CVE/secnote-2026-04.txt
- https://github.com/nats-io/nats-server/commit/a1488de6f2ba6e666aef0f9cce0016f7f167d6a8
- https://github.com/nats-io/nats-server/security/advisories/GHSA-52jh-2xxh-pwh6
- https://access.redhat.com/errata/RHSA-2026:21769
- https://access.redhat.com/errata/RHSA-2026:22347
- https://access.redhat.com/errata/RHSA-2026:23345
- https://access.redhat.com/security/cve/CVE-2026-29785
- https://bugzilla.redhat.com/show_bug.cgi?id=2451444
- https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-29785.json