CVE-2026-29785

highpriority · track · 0EPSS 0.007 · 52 %ileDEEUUS

grimoire priorityP2 · Scheduled

Exploitable?

—

no known exploitation

Likely / severe?

0.68% (52nd) EPSS

CVSS 7.5 · high

Is it mine?

14 products

Check your exposure

Who says so?

5 sources

cnnvd · enisa_euvd · osv · cert_bund

EPSS · scored 2026-10-27

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.

cvss

Technical severity, 0–10. One row per scoring source.

7.5

010

base score 0–10 · higher = more severe · hover a vector to decode

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · ENISA EU

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · security-advisories@github.comexploitability 3.9 · impact 3.6

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondaryexploitability 3.9 · impact 3.6

v3.17.5highCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Hsecondary · OSV

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: yes · Technical Impact: partialcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-409USCWE-476USCWE-476US

affected products (14)

Products and version ranges known to be affected.

Open Source NATS Server <v2.11.14all versionscert_bundDE
Open Source NATS Server <v2.12.5all versionscert_bundDE
Red Hat Enterprise Linuxall versionscert_bundDEcpe:/o:redhat:enterprise_linux:-
Open Source NATS Server< v2.11.14cert_bundDE
Open Source NATS Server< v2.12.5cert_bundDE
nats-io nats-server≤ < 2.11.14enisa_euvdEU
nats-io nats-server2.12.0-RC.1, → 2.12.5enisa_euvdEU
linuxfoundation nats-server< 2.11.14nvdUScpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*
linuxfoundation nats-server2.12.0 → 2.12.5nvdUScpe:2.3:a:linuxfoundation:nats-server:*:*:*:*:*:*:*:*
Bitnami nats< 2.11.14osvUSpkg:bitnami/nats
Bitnami nats2.12.0 → 2.12.5osvUSpkg:bitnami/nats
Go github.com/nats-io/nats-serverall versionsosvUSpkg:golang/github.com/nats-io/nats-server
Go github.com/nats-io/nats-server/v2< 2.11.14osvUSpkg:golang/github.com/nats-io/nats-server/v2
Go github.com/nats-io/nats-server/v22.12.0-RC.1 → 2.12.5osvUSpkg:golang/github.com/nats-io/nats-server/v2

advisories (4)

Vendor and ecosystem advisories describing this.

WID-SEC-W-2026-0641NATS Server: Mehrere Schwachstellen ermöglichen Denial of ServiceDeutsch2026-03-09csaf · cert_bundDE
Ein entfernter, anonymer Angreifer kann mehrere Schwachstellen in NATS Server ausnutzen, um einen Denial of Service Angriff durchzuführen.
GHSA-52jh-2xxh-pwh6NATS Server panic via malicious compression on leafnode port2026-03-24ghsa · osvUS
### Background NATS.io is a high performance open source pub-sub distributed communication technology, built for the cloud, on-premise, IoT, and edge computing. When configured to accept leafnode connections (for a hub/spoke topology of multiple nats-servers), then the default configuration allows for negotiating compression; a malicious remote NATS server can trigger a server panic via that compression. ### Problem Description 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). Context: a NATS server can form various clustering topologies, including local clusters, and superclusters of clusters, but leafnodes allow for separate administrative domains to link together with limited data communication; eg, a server in a moving vehicle might use a local leafnode for agents to connect to, and sync up to a central service as and when available. The leafnode configuration here is where the central server allows other NATS servers to connect into it, almost like regular NATS clients. Documentation examples typically use port 7422 for leafnode communications. ### Affected Versions Version 2, prior to v2.11.14 or v2.12.5 ### Workarounds Disable compression on the leafnode port: ``` leafnodes { port: 7422 compression: off } ```
BIT-nats-2026-29785NATS Server panic via malicious compression on leafnode port2026-03-27vendor · osvUS
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.
GO-2026-4829NATS Server panic via malicious compression on leafnode port in github.com/nats-io/nats-server2026-03-26vendor · osvUS
NATS Server panic via malicious compression on leafnode port in github.com/nats-io/nats-server

also known as (6)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd osv cert_bund nvd NVD CVE.org MITRE

published 2026-03-25modified 2026-09-09

references (17)

External citations — patches, advisories, analysis.

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