5.4

CVE-2026-58211: linuxfoundation nats-server Incorrect Authorization

CVSS: 5.4v3.1MediumAnalyzed
AliasesUBUNTU-CVE-2026-58211DEBIAN-CVE-2026-58211
Published 08-07-2026Last modified 09-07-2026
Open JSON

Vulnerability summary

CVE-2026-58211 is a medium (CVSS 5.4) Incorrect Authorization vulnerability in linuxfoundation nats-server. EPSS estimates a 0.29% chance of exploitation in the next 30 days, higher than 20.4% of scored vulnerabilities.

Overall risk
22/100
0100
Low · default modelHow is this calculated?
CVSS score
5.4/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.29%
0%100%
Low · 0.00 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
RHSA-2026:36016RHSA-2026:36017

Timeline

  1. 08-07-2026
    PublishedVulnerability first disclosed.
  2. 09-07-2026
    Last modifiedVulnerability information updated.

Description

NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.14.3 and 2.12.12, a client could be registered as the configured no_auth_user through a parser path used when the first client operation was not CONNECT, bypassing user-level connection restrictions such as allowed_connection_types or proxy_required that normal authentication would apply. This issue is fixed in versions 2.14.3 and 2.12.12.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.29%

Chance of exploitation in the next 30 days

Percentile

20%

Versus all other CVEs

30-day change

0.00 pp

From 0.29% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.29%

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

Debian1 product
  • nats-serverAll versions (No fix recorded) | < 2.14.3-1
Linuxfoundation1 product
  • nats-server≥ 2.12.0, < 2.12.12 | ≥ 2.14.0, < 2.14.3
Nats-io1 product
Ubuntu1 product
  • nats-serverAll versions (No fix recorded)

4 vendors · 4 products

References

4 links