NATS Server panic via malicious compression on leafnode port
Summary
| CVE | CVE-2026-29785 |
|---|---|
| State | PUBLISHED |
| Assigner | GitHub_M |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-03-25 20:16:30 UTC |
| Updated | 2026-07-20 12:18:26 UTC |
| 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. |
Risk And Classification
Primary CVSS: v3.1 7.5 HIGH from ADP
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Problem Types: CWE-476 | CWE-409 | CWE-476 CWE-476: NULL Pointer Dereference | CWE-409 Improper Handling of Highly Compressed Data (Data Amplification)
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | ADP | CVSS | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | [email protected] | Secondary | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | Secondary | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | CNA | DECLARED | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
CVSS v3.1 Breakdown
Attack Vector
NetworkAttack Complexity
LowPrivileges Required
NoneUser Interaction
NoneScope
UnchangedConfidentiality
NoneIntegrity
NoneAvailability
HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
NVD Known Affected Configurations (CPE 2.3)
| Type | Vendor | Product | Version | Update | Edition | Language |
|---|---|---|---|---|---|---|
| Application | Linuxfoundation | Nats-server | All | All | All | All |
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | Nats-io | Nats-server | affected < 2.11.14 | Not specified |
| CNA | Nats-io | Nats-server | affected >= 2.12.0-RC.1, < 2.12.5 | Not specified |
| ADP | Red Hat | Multicluster Global Hub 1.5.4 | unaffected 1778867753 * rpm | Not specified |
| ADP | Red Hat | Multicluster Global Hub 1.6.2 | unaffected 1780167118 * rpm | Not specified |
| ADP | Red Hat | Red Hat Multicluster Global Hub 1.4.3 | unaffected 1779579439 * rpm | Not specified |
| ADP | Red Hat | Red Hat OpenShift Container Platform 4 | Not specified | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| access.redhat.com/errata/RHSA-2026:21769 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/security/cve/CVE-2026-29785 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| access.redhat.com/errata/RHSA-2026:23345 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-29785.json | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | security.access.redhat.com | |
| github.com/nats-io/nats-server/commit/a1488de6f2ba6e666aef0f9cce0016f7f1... | [email protected] | github.com | Patch |
| github.com/nats-io/nats-server/security/advisories/GHSA-52jh-2xxh-pwh6 | [email protected] | github.com | Mitigation, Vendor Advisory |
| access.redhat.com/errata/RHSA-2026:22347 | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | access.redhat.com | |
| advisories.nats.io/CVE/secnote-2026-04.txt | [email protected] | advisories.nats.io | Mitigation, Vendor Advisory |
| bugzilla.redhat.com/show_bug.cgi | 0b0ca135-0b70-47e7-9f44-1890c2a1c46c | bugzilla.redhat.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
No vendor comments have been submitted for this CVE.
Additional Advisory Data
| Source | Time | Event |
|---|---|---|
| ADP | 2026-03-25T20:01:35.121Z | Reported to Red Hat. |
| ADP | 2026-03-25T19:38:44.587Z | Made public. |
Solutions
ADP: RHSA-2026:22347: Multicluster Global Hub 1.4.5
ADP: RHSA-2026:23345: Multicluster Global Hub 1.6.2
ADP: RHSA-2026:21769: Red Hat multicluster global hub 1.5.2
Workarounds
ADP: Mitigation for this issue is either not available or the currently available options do not meet the Red Hat Product Security criteria comprising ease of use and deployment, applicability to widespread installation base or stability.
There are currently no legacy QID mappings associated with this CVE.