CVE-2026-58251: CWE-285: Improper Authorization in nats-io nats-server
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.
AI Analysis
Technical Summary
CVE-2026-58251 is an improper authorization vulnerability (CWE-285) in nats-io nats-server. Before versions 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 leveraging queue subscriptions. The queue-specific deny evaluation could override the plain subject deny result if the queue name itself was not denied, allowing unauthorized subscription to subjects that should have been denied. This vulnerability is resolved in the stated fixed versions.
Potential Impact
An authenticated user with subscription deny permissions could bypass intended access controls on messaging subjects by exploiting queue subscription behavior. This could lead to unauthorized access to messages on subjects that were supposed to be denied, resulting in confidentiality impact. There is no indication of integrity or availability impact. No known exploits in the wild have been reported.
Mitigation Recommendations
Upgrade nats-server to version 2.14.0, 2.12.7, or 2.11.16 or later, where this vulnerability is fixed. Patch status is confirmed by the vendor's versioning information. No other mitigation is indicated.
CVE-2026-58251: CWE-285: Improper Authorization in nats-io nats-server
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.
CVSS v3.1
Score 6.5medium
Affected software
pkg:github/nats-io/nats-serverRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
CVE-2026-58251 is an improper authorization vulnerability (CWE-285) in nats-io nats-server. Before versions 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 leveraging queue subscriptions. The queue-specific deny evaluation could override the plain subject deny result if the queue name itself was not denied, allowing unauthorized subscription to subjects that should have been denied. This vulnerability is resolved in the stated fixed versions.
Potential Impact
An authenticated user with subscription deny permissions could bypass intended access controls on messaging subjects by exploiting queue subscription behavior. This could lead to unauthorized access to messages on subjects that were supposed to be denied, resulting in confidentiality impact. There is no indication of integrity or availability impact. No known exploits in the wild have been reported.
Mitigation Recommendations
Upgrade nats-server to version 2.14.0, 2.12.7, or 2.11.16 or later, where this vulnerability is fixed. Patch status is confirmed by the vendor's versioning information. No other mitigation is indicated.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- GitHub_M
- Date Reserved
- 2026-06-29T21:54:30.330Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- null
Threat ID: 6a4ea886c9d9e3dbe3a5251e
Added to database: 07/08/2026, 19:44:06 UTC
Last enriched: 07/16/2026, 10:13:07 UTC
Last updated: 08/22/2026, 12:15:37 UTC
Views: 72
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