CVE-2026-58214 | NATS Server is a high-performance server for NATS.io, the cl… | CVSS 4.3 MEDIUM

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, an authenticated MQTT client could subscribe to the internal $MQTT.deliver.pubrel subject family, bypassing configured subscribe permissions and exposing MQTT QoS2 protocol metadata for sessions in the account. This issue is fixed in versions 2.14.3 and 2.12.12.

Metadata

CVE ID: CVE-2026-58214
State: PUBLISHED
Assigner: GitHub_M
Reserved: 2026-06-29 17:09 UTC
Published: 2026-07-08 20:06 UTC
Last updated: 2026-07-08 20:06 UTC
Primary CWE: CWE-863
CWE-863: Incorrect Authorization
Vendor / Product: nats-io / nats-server
Sources: cve.org · NVD

Severity & Metrics

4.3 MEDIUM CVSS 3.1

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

Affected products (1)

Vendor	Product	Platform	Versions
nats-io	nats-server	—	< 2.12.12, >= 2.14.0-RC.1, < 2.14.3

Weakness (CWE)

CWE	Source	Description
CWE-863	cna	CWE-863: Incorrect Authorization

CVSS scores (1)

Score	Severity	Version	Source	Vector
4.3	MEDIUM	3.1	cna	CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

References (5)

https://github.com/nats-io/nats-server/security/advisories/GHSA-4g68-3pwx-5vfj https://github.com/nats-io/nats-server/security/advisories/GHSA-4g68-3pwx-5vfj
https://github.com/nats-io/nats-server/commit/297b166be60fe13144084eed4b25201ead03204a https://github.com/nats-io/nats-server/commit/297b166be60fe13144084eed4b25201ead03204a
https://github.com/nats-io/nats-server/commit/34b09657bb596d5f850eaa5cfc97ea6b2f989a97 https://github.com/nats-io/nats-server/commit/34b09657bb596d5f850eaa5cfc97ea6b2f989a97
https://github.com/nats-io/nats-server/releases/tag/v2.12.12 https://github.com/nats-io/nats-server/releases/tag/v2.12.12
https://github.com/nats-io/nats-server/releases/tag/v2.14.3 https://github.com/nats-io/nats-server/releases/tag/v2.14.3