4.3

CVE-2026-58209: linuxfoundation nats-server Incorrect Authorization

CVSS: 4.3v3.1MediumAnalyzed
AliasesUBUNTU-CVE-2026-58209DEBIAN-CVE-2026-58209
Published 08-07-2026Last modified 09-07-2026
Open JSON

Vulnerability summary

CVE-2026-58209 is a medium (CVSS 4.3) Incorrect Authorization vulnerability in linuxfoundation nats-server. EPSS estimates a 0.34% chance of exploitation in the next 30 days, higher than 26.2% 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
0.34%
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, MQTT retained message delivery and QoS1+ durable replay could deliver messages whose original topics matched a subscriber configured subscribe deny rule because these delivery paths did not consistently recheck the concrete original topic before sending the MQTT PUBLISH to the subscriber. This issue is fixed in versions 2.14.3 and 2.12.12.

CVSS metrics

4 scores · 4 sources · 1 version

EPSS trend

Probability

0.34%

Chance of exploitation in the next 30 days

Percentile

26%

Versus all other CVEs

30-day change

0.00 pp

From 0.34% on 19-09-2026

19-09-202619-10-2026
EPSS score
0.34%

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-io1 product
Ubuntu1 product
  • nats-serverAll versions (No fix recorded)

4 vendors · 4 products

References

9 links