UBUNTU-CVE-2026-58253
NATS Server versions prior to 2.14.0, 2.12.7, and 2.11.16 contain a vulnerability where the no_auth_user configuration allows an unauthenticated peer to bypass inter-server CONNECT authentication. This occurs because a parser fast path intended for ordinary client connections also applies to route or leafnode listeners, granting unauthorized access with elevated privileges. The issue is fixed in versions 2.14.0, 2.12.7, and 2.11.16. Several Ubuntu package versions are affected by this vulnerability.
AI Analysis
Technical Summary
The NATS Server, a messaging system component, has a vulnerability in versions prior to 2.14.0, 2.12.7, and 2.11.16 when configured with no_auth_user. A parser optimization intended for ordinary client connections is incorrectly applied to route or leafnode listeners, allowing an unauthenticated peer to bypass inter-server CONNECT authentication. This bypass grants the peer the privileges associated with the connection type, potentially allowing unauthorized actions within the messaging system. The vulnerability is resolved in the specified fixed versions.
Potential Impact
An unauthenticated attacker can bypass inter-server authentication mechanisms and operate with the privileges of route or leafnode connections. This can lead to unauthorized access and potentially high impact on integrity and low impact on availability of the messaging system. Confidentiality impact is low but integrity impact is high due to unauthorized operation capabilities.
Mitigation Recommendations
Upgrade NATS Server to versions 2.14.0, 2.12.7, or 2.11.16 or later where this vulnerability is fixed. The affected Ubuntu package versions listed should be updated to the fixed versions provided by the vendor or distribution. No other mitigation is indicated by the vendor advisory.
UBUNTU-CVE-2026-58253
Description
NATS Server versions prior to 2.14.0, 2.12.7, and 2.11.16 contain a vulnerability where the no_auth_user configuration allows an unauthenticated peer to bypass inter-server CONNECT authentication. This occurs because a parser fast path intended for ordinary client connections also applies to route or leafnode listeners, granting unauthorized access with elevated privileges. The issue is fixed in versions 2.14.0, 2.12.7, and 2.11.16. Several Ubuntu package versions are affected by this vulnerability.
CVSS v3.1
Score 8.8high
Affected software
pkg:deb/ubuntu/[email protected]?arch=source&distro=noblepkg:deb/ubuntu/[email protected]?arch=source&distro=questingpkg:deb/ubuntu/[email protected]~esm1?arch=source&distro=esm-apps/resoluteRun on your own infrastructure? Check whether these packages are installed with threat-finder — our free open-source scanner.
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
The NATS Server, a messaging system component, has a vulnerability in versions prior to 2.14.0, 2.12.7, and 2.11.16 when configured with no_auth_user. A parser optimization intended for ordinary client connections is incorrectly applied to route or leafnode listeners, allowing an unauthenticated peer to bypass inter-server CONNECT authentication. This bypass grants the peer the privileges associated with the connection type, potentially allowing unauthorized actions within the messaging system. The vulnerability is resolved in the specified fixed versions.
Potential Impact
An unauthenticated attacker can bypass inter-server authentication mechanisms and operate with the privileges of route or leafnode connections. This can lead to unauthorized access and potentially high impact on integrity and low impact on availability of the messaging system. Confidentiality impact is low but integrity impact is high due to unauthorized operation capabilities.
Mitigation Recommendations
Upgrade NATS Server to versions 2.14.0, 2.12.7, or 2.11.16 or later where this vulnerability is fixed. The affected Ubuntu package versions listed should be updated to the fixed versions provided by the vendor or distribution. No other mitigation is indicated by the vendor advisory.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- UBUNTU-CVE-2026-58253
- Osv Schema Version
- 1.7.0
- Aliases
- []
- Ecosystems
- ["Ubuntu:24.04:LTS","Ubuntu:25.10","Ubuntu:Pro:26.04:LTS"]
- Database Specific Severity
- null
- Cvss Version
- 3.1
Threat ID: 6a58b45d68715ace43d6be26
Added to database: 07/16/2026, 10:37:17 UTC
Last enriched: 07/16/2026, 11:35:26 UTC
Last updated: 07/31/2026, 19:24:49 UTC
Views: 4
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