CVE-2026-33219
Medium · 5.3CVSS
5.3
EPSS
1.0%
Published
Mar 25, 2026
CISA due date
—
The record
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 malicious client which can connect to the WebSockets port can cause unbounded memory use in the nats-server before authentication; this requires sending a corresponding amount of data. This is a milder variant of CVE-2026-27571. That earlier issue was a compression bomb, this vulnerability is not. Attacks against this new issue thus require significant client bandwidth. Versions 2.11.15 and 2.12.6 contain a fix. As a workaround, disable websockets if not required for project deployment.
Affected packages
| Ecosystem | Package | Introduced | Fixed |
|---|---|---|---|
| Chainguard | k3s | 0 | 1.35.2.1-r4 |
| Chainguard | k3s-1.32 | 0 | 1.32.13.1-r7 |
| Chainguard | k3s-1.33 | 0 | 1.33.9.1-r6 |
| Chainguard | k3s-static | 0 | 1.35.2.1-r4 |
| Chainguard | k3s-static-1.32 | 0 | 1.32.13.1-r7 |
| Chainguard | k3s-static-1.33 | 0 | 1.33.9.1-r6 |
| Chainguard | kine | 0 | 0.14.15-r1 |
| Chainguard | milvus-2.5 | 0 | 2.5.27-r4 |
| Chainguard | nats | 0 | 0.3.2-r0 |
| Chainguard | nats-fips | 0 | 0.3.2-r0 |
| Chainguard | nats-top | 0 | 0.6.3-r18 |
| Chainguard | nats-top-fips | 0 | 0.6.3-r16 |
| Chainguard | prometheus-nats-exporter | 0 | 0.19.1-r4 |
| Chainguard | prometheus-nats-exporter-fips | 0 | 0.19.1-r4 |
| Chainguard | rke2-runtime-1.33 | 0 | 1.33.9.2.1-r3 |
| Chainguard | rke2-runtime-1.34 | 0 | 1.34.5.2.1-r3 |
| Chainguard | rke2-runtime-1.35 | 0 | 1.35.2.2.1-r3 |
| Chainguard | rke2-runtime-fips-1.34 | 0 | 1.34.6.2.1-r2 |
| Chainguard | rke2-runtime-fips-1.35 | 0 | 1.35.2.2.1-r2 |
| Chainguard | telegraf-1.37 | 0 | 1.37.3-r6 |
| Chainguard | telegraf-1.38 | 0 | 1.38.1-r1 |
| Wolfi | k3s | 0 | 1.35.2.1-r4 |
| Wolfi | k3s-1.32 | 0 | 1.32.13.1-r7 |
| Wolfi | k3s-1.33 | 0 | 1.33.9.1-r6 |
| Wolfi | k3s-static | 0 | 1.35.2.1-r4 |
| Wolfi | k3s-static-1.32 | 0 | 1.32.13.1-r7 |
| Wolfi | k3s-static-1.33 | 0 | 1.33.9.1-r6 |
| Wolfi | kine | 0 | 0.14.15-r1 |
| Wolfi | nats | 0 | 0.3.2-r0 |
| Wolfi | nats-top | 0 | 0.6.3-r18 |
| Wolfi | prometheus-nats-exporter | 0 | 0.19.1-r4 |
| Wolfi | telegraf-1.37 | 0 | 1.37.3-r6 |
| Wolfi | telegraf-1.38 | 0 | 1.38.1-r1 |
| openSUSE:Leap 15.6 | govulncheck-vulndb | 0 | 0.0.20260326T203309-150000.1.155.2 |
Related vulnerabilities
- CVE-2026-32241 Flannel is a network fabric for containers, designed for Kubernetes. Also affects k3s
- CVE-2026-32285 The Delete function fails to properly validate offsets when processing malformed JSON… Also affects k3s
- CVE-2026-33249 NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging… Also affects k3s
- CVE-2026-33248 NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging… Also affects k3s
- CVE-2026-33222 NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging… Also affects k3s
- CVE-2026-33223 NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging… Also affects k3s
- CVE-2026-33246 NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging… Also affects k3s
- CVE-2026-33247 NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging… Also affects k3s