High severityNVD Advisory· Published Mar 25, 2026· Updated Mar 26, 2026
NATS has pre-auth server panic via leafnode handling
CVE-2026-33218
Description
NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, a client which can connect to the leafnode port can crash the nats-server with a certain malformed message pre-authentication. Versions 2.11.15 and 2.12.6 contain a fix. As a workaround, disable leafnode support if not needed or restrict network connections to the leafnode port, if plausible without compromising the service offered.
AI Insight
LLM-synthesized narrative grounded in this CVE's description and references.
Affected packages
Versions sourced from the GitHub Security Advisory.
| Package | Affected versions | Patched versions |
|---|---|---|
github.com/nats-io/nats-server/v2Go | < 2.11.15 | 2.11.15 |
github.com/nats-io/nats-server/v2Go | >= 2.12.0-RC.1, < 2.12.6 | 2.12.6 |
github.com/nats-io/nats-serverGo | >= 0 | — |
Affected products
39- osv-coords38 versionspkg:apk/chainguard/k3spkg:apk/chainguard/k3s-1.32pkg:apk/chainguard/k3s-1.33pkg:apk/chainguard/k3s-staticpkg:apk/chainguard/k3s-static-1.32pkg:apk/chainguard/k3s-static-1.33pkg:apk/chainguard/kinepkg:apk/chainguard/milvus-2.5pkg:apk/chainguard/natspkg:apk/chainguard/nats-fipspkg:apk/chainguard/nats-toppkg:apk/chainguard/nats-top-fipspkg:apk/chainguard/prometheus-nats-exporterpkg:apk/chainguard/prometheus-nats-exporter-fipspkg:apk/chainguard/rke2-runtime-1.33pkg:apk/chainguard/rke2-runtime-1.34pkg:apk/chainguard/rke2-runtime-1.35pkg:apk/chainguard/rke2-runtime-fips-1.33pkg:apk/chainguard/rke2-runtime-fips-1.34pkg:apk/chainguard/rke2-runtime-fips-1.35pkg:apk/chainguard/telegraf-1.37pkg:apk/chainguard/telegraf-1.38pkg:apk/wolfi/k3spkg:apk/wolfi/k3s-1.32pkg:apk/wolfi/k3s-1.33pkg:apk/wolfi/k3s-staticpkg:apk/wolfi/k3s-static-1.32pkg:apk/wolfi/k3s-static-1.33pkg:apk/wolfi/kinepkg:apk/wolfi/natspkg:apk/wolfi/nats-toppkg:apk/wolfi/prometheus-nats-exporterpkg:apk/wolfi/telegraf-1.37pkg:apk/wolfi/telegraf-1.38pkg:bitnami/natspkg:golang/github.com/nats-io/nats-serverpkg:golang/github.com/nats-io/nats-server/v2pkg:rpm/opensuse/govulncheck-vulndb&distro=openSUSE%20Leap%2015.6
< 1.35.2.1-r4+ 37 more
- (no CPE)range: < 1.35.2.1-r4
- (no CPE)range: < 1.32.13.1-r7
- (no CPE)range: < 1.33.9.1-r6
- (no CPE)range: < 1.35.2.1-r4
- (no CPE)range: < 1.32.13.1-r7
- (no CPE)range: < 1.33.9.1-r6
- (no CPE)range: < 0.14.15-r1
- (no CPE)range: < 2.5.27-r4
- (no CPE)range: < 0.3.2-r0
- (no CPE)range: < 0.3.2-r0
- (no CPE)range: < 0.6.3-r18
- (no CPE)range: < 0.6.3-r16
- (no CPE)range: < 0.19.1-r4
- (no CPE)range: < 0.19.1-r4
- (no CPE)range: < 1.33.9.2.1-r3
- (no CPE)range: < 1.34.5.2.1-r3
- (no CPE)range: < 1.35.2.2.1-r3
- (no CPE)range: < 1.33.10.2.3-r2
- (no CPE)range: < 1.34.6.2.1-r2
- (no CPE)range: < 1.35.2.2.1-r2
- (no CPE)range: < 1.37.3-r6
- (no CPE)range: < 1.38.1-r1
- (no CPE)range: < 1.35.2.1-r4
- (no CPE)range: < 1.32.13.1-r7
- (no CPE)range: < 1.33.9.1-r6
- (no CPE)range: < 1.35.2.1-r4
- (no CPE)range: < 1.32.13.1-r7
- (no CPE)range: < 1.33.9.1-r6
- (no CPE)range: < 0.14.15-r1
- (no CPE)range: < 0.3.2-r0
- (no CPE)range: < 0.6.3-r18
- (no CPE)range: < 0.19.1-r4
- (no CPE)range: < 1.37.3-r6
- (no CPE)range: < 1.38.1-r1
- (no CPE)range: < 2.11.15
- (no CPE)range: >= 0
- (no CPE)range: < 2.11.15
- (no CPE)range: < 0.0.20260326T203309-150000.1.155.2
- Range: < < 2.11.15
Patches
Vulnerability mechanics
References
4- github.com/advisories/GHSA-vprv-35vv-q339ghsaADVISORY
- nvd.nist.gov/vuln/detail/CVE-2026-33218ghsaADVISORY
- advisories.nats.io/CVE/secnote-2026-10.txtghsax_refsource_MISCWEB
- github.com/nats-io/nats-server/security/advisories/GHSA-vprv-35vv-q339ghsax_refsource_CONFIRMWEB
News mentions
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