4.3

CVE-2026-33249: linuxfoundation nats-server Incorrect Authorization

CVSS: 4.3v3.1MediumAnalyzed
AliasesUBUNTU-CVE-2026-33249DEBIAN-CVE-2026-33249CGA-35qp-jcfp-rrcr
Published 25-03-2026Last modified 26-03-2026
Open JSON

Vulnerability summary

CVE-2026-33249 is a medium (CVSS 4.3) Incorrect Authorization vulnerability in linuxfoundation nats-server. EPSS estimates a 0.26% chance of exploitation in the next 30 days, higher than 17.2% of scored vulnerabilities.

Overall risk
17/100
0100
Low · default modelHow is this calculated?
CVSS score
4.3/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.26%
0%100%
Low · +0.04 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 2 · Related 3
OPENSUSE-SU-2026:21483-1SUSE-SU-2026:1135-1CGA-J4Q2-4FXJ-9R3H

Timeline

  1. 25-03-2026
    PublishedVulnerability first disclosed.
  2. 26-03-2026
    Last modifiedVulnerability information updated.

Description

NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Starting in version 2.11.0 and prior to versions 2.11.15 and 2.12.6, a valid client which uses message tracing headers can indicate that the trace messages can be sent to an arbitrary valid subject, including those to which the client does not have publish permission. The payload is a valid trace message and not chosen by the attacker. Versions 2.11.15 and 2.12.6 contain a fix. No known workarounds are available.

CVSS metrics

7 scores · 7 sources · 1 version

EPSS trend

Probability

0.26%

Chance of exploitation in the next 30 days

Percentile

17%

Versus all other CVEs

30-day change

+0.04 pp

From 0.23% on 20-09-2026

20-09-202620-10-2026
EPSS score
0.26%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Chainguard28 products
  • k3s< 1.35.2.1-r4
  • k3s-1.32< 1.32.13.1-r7
  • k3s-1.33< 1.33.9.1-r6
  • k3s-static< 1.35.2.1-r4
  • k3s-static-1.32< 1.32.13.1-r7
Wolfi12 products
  • k3s< 1.35.2.1-r4
  • k3s-1.32< 1.32.13.1-r7
  • k3s-1.33< 1.33.9.1-r6
  • k3s-static< 1.35.2.1-r4
  • k3s-static-1.32< 1.32.13.1-r7
Debian1 product
  • nats-server< 2.12.6-1
Github.com/nats-io1 product
  • nats-serverAll versions (No fix recorded)
Github.com/nats-io/nats-server1 product
  • v2≥ 2.11.0, < 2.11.15 | ≥ 2.12.0-preview.1, < 2.12.6
Linuxfoundation1 product
  • nats-server≥ 2.11.0, < 2.11.15 | ≥ 2.12.0, < 2.12.6
Nats-io1 product
  • nats-server≥ 2.11.0, < 2.11.15 | ≥ 2.12.0-preview.1, < 2.12.6
Ubuntu1 product
  • nats-serverAll versions (No fix recorded)

8 vendors · 46 products

References

8 links