High 8.8Published Jul 8, 2026

CVE-2026-58253NATS Server: Route API Auth Bypass

Updated under an hour ago (Oct 26, 2026, 12:40 PM ET)

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No exploitation reported and no EPSS estimate yet.

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Exploited in the last 30 days

NATS Server is a high-performance server for NATS.io, the cloud and edge native messaging system. Prior to 2.14.0, 2.12.7, and 2.11.16, when no_auth_user was configured, a parser fast path intended for ordinary client connections could also apply to route or leafnode listeners, allowing an unauthenticated peer to bypass inter-server CONNECT authentication and operate with the privileges associated with that connection type. This issue is fixed in versions 2.14.0, 2.12.7, and 2.11.16.

CVSS: 8.8 HIGH (v3.1, CNA)CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:C/C:L/I:H/A:L
Weakness (CWE): CWE-287
Known exploited: Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days): Not loaded for this CVE
Assigned by: GitHub_M
NVD analysis: Analyzed
Record last updated: Jul 9, 2026
First seen by InfoSec Signals: Oct 9, 2026

Affected products

Affected products

nats-io nats-server nats_io:nats_server (from the name)	before 2.11.16; from 2.12.0-preview.1, < 2.12.6	CNA record
linuxfoundation nats-server linuxfoundation:nats-server	before 2.11.16; from 2.12.0 before 2.12.7	NVD

References

References

https://github.com/nats-io/nats-server/security/advisories/GHSA-38x3-76xf-cq45	x-refsource-confirm, vendor-advisory
https://github.com/nats-io/nats-server/commit/7b81dd455ea95960090a84858c7662827948d1b6	x-refsource-misc, patch
https://github.com/nats-io/nats-server/commit/8b8e1ad4ceed32321e00d4fc6e76be05bc13bca6	x-refsource-misc, patch
https://github.com/nats-io/nats-server/commit/b86147e81710a52b72a7f7275f91d69f723f5cb3	x-refsource-misc, patch
https://github.com/nats-io/nats-server/releases/tag/v2.11.16	x-refsource-misc, release-notes
https://github.com/nats-io/nats-server/releases/tag/v2.12.7	x-refsource-misc, release-notes
https://github.com/nats-io/nats-server/releases/tag/v2.14.0	x-refsource-misc, release-notes

The CVE record on cve.org NVD's entry

The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.