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.

No CVSS v4.0

Attack Vector Network

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact Low

Integrity Impact None

Availability Impact None

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

No EPSS score available.

Key SSVC decision points have not yet been added.

Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).

Vendor Product Default status Versions
nats-io nats-server affected
Version Status Constraints
< 2.12.12 affected —
>= 2.14.0-RC.1, < 2.14.3 affected —

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Project Subscriptions

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Advisories

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Fixes

Solution

No solution given by the vendor.

Workaround

No workaround given by the vendor.

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

Wed, 08 Jul 2026 20:15:00 +0000

Type Values Removed Values Added
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.
Title NATS Server: MQTT subscribe ACL bypass via $MQTT.deliver.pubrel prefix (incomplete fix for CVE-2026-33217)
Weaknesses CWE-863
References
Metrics cvssV3_1

{'score': 4.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N'}

Projects

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cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-07-08T20:06:34.794Z

Reserved: 2026-06-29T17:09:25.873Z

Link: CVE-2026-58214

cve-icon Vulnrichment

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cve-icon NVD

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cve-icon Redhat

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cve-icon OpenCVE Enrichment

Updated: 2026-07-09T09:30:04Z

Weaknesses