CVE-2026-58209

MEDIUMPre-NVD 4.34.3—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 4.3 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 74% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Trending — 3 sources updated this week
4.3
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS: 0%CVSS: 4.3Exploit: NoneExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

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 v3
4.3
EG Score
4.3(medium)
EPSS
26.3%
KEV
Not listed

Published

July 8, 2026

Last Modified

July 13, 2026

Advisory Details (5)

Auto-updated Jul 8, 2026
Patch available. Sources: github_commit, github_release, github.
github Patch Available

MQTT retained and QoS replay bypass subscribe deny filters · Advisory · nats-io/nats-server · GitHub

Affected: v2.14.3 and v2.12.12.

https://github.com/nats-io/nats-server/security/advisories/GHSA-7qmq-8cc4-hxwg
github_release Patch Available

Release v2.14.3

Patch available: nats-io/nats-server v2.14.3

https://github.com/nats-io/nats-server/releases/tag/v2.14.3
github_release Patch Available

Release v2.12.12

Patch available: nats-io/nats-server v2.12.12

https://github.com/nats-io/nats-server/releases/tag/v2.12.12
github_commit

commit 1c429b6fdc5a (nats-io/nats-server)

Fix landed in nats-io/nats-server commit 1c429b6fdc5a — awaiting tagged release

https://github.com/nats-io/nats-server/commit/1c429b6fdc5afd4188cc5faf1127f6334896cd87
github_commit

commit 181b1f51f40b (nats-io/nats-server)

Fix landed in nats-io/nats-server commit 181b1f51f40b — awaiting tagged release

https://github.com/nats-io/nats-server/commit/181b1f51f40b9954c57e9d478e051fb257679356

Vendor Advisories for CVE-2026-58209(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 18× in last 7d / 18× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-07-15 02:00 UTCEPSS rescore
  2. 2026-07-15 02:00 UTCEPSS rescore
  3. 2026-07-15 01:11 UTCEG score recompute
  4. 2026-07-14 00:22 UTCEG score recompute
  5. 2026-07-13 22:31 UTCEPSS rescore
  6. 2026-07-13 06:13 UTCEPSS rescore
  7. 2026-07-13 06:13 UTCEPSS rescore
  8. 2026-07-12 23:32 UTCEG score recompute
  9. 2026-07-12 05:46 UTCEPSS rescore
  10. 2026-07-11 22:43 UTCEG score recompute
  11. 2026-07-11 08:27 UTCEPSS rescore
  12. 2026-07-11 08:27 UTCEPSS rescore
  13. 2026-07-10 21:54 UTCEG score recompute
  14. 2026-07-09 21:05 UTCEG score recompute
  15. 2026-07-09 19:10 UTCEPSS rescore
  16. 2026-07-09 19:10 UTCEPSS rescore
  17. 2026-07-08 20:16 UTCEG score recompute
  18. 2026-07-08 20:14 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(5)

What is CVE-2026-58209?
CVE-2026-58209 is a medium vulnerability published on July 8, 2026. 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…
When was CVE-2026-58209 disclosed?
CVE-2026-58209 was first published in the National Vulnerability Database on July 8, 2026, with the most recent update on July 13, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-58209 actively exploited?
CVE-2026-58209 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 26.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.
What is the CVSS score of CVE-2026-58209?
CVE-2026-58209 has a CVSS v3 base score of 4.3 (NVD).
How do I remediate CVE-2026-58209?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-58209, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

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