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Vulnerability · Published Jul 8, 2026 · Assigned by GitHub_M

CVE-2026-58251NATS Server: Queue Subscribe Authz Bypass

Medium 6.5

In plain English

A medium-severity security flaw in nats-server from nats-io. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.5% (higher than 40% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)6.5Medium
Exploit odds (30 days)0.5%top 59.7% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

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, an authenticated user with subscription deny permissions could bypass a plain subject deny rule by using a queue subscription, because queue-specific deny evaluation could override the plain subject deny result when the queue name itself was not denied. This issue is fixed in versions 2.14.0, 2.12.7, and 2.11.16.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12nats-serverno fix listedDEBIAN-CVE-2026-58251
Debian:13nats-serverno fix listedDEBIAN-CVE-2026-58251
Debian:14nats-server2.14.1-1DEBIAN-CVE-2026-58251
Ubuntu:24.04:LTSnats-serverno fix listedUBUNTU-CVE-2026-58251
Ubuntu:25.10nats-serverno fix listedUBUNTU-CVE-2026-58251

Affected products (as reported)

VendorProductVersions
nats-io nats-server < 2.11.16>= 2.12.0-RC.1, < 2.12.7

Weakness: CWE-285 · Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N

References