NATS Server: MQTT partial CONNECT packets can exhaust pre-auth memory (CVE-2026-58210)
NATS Server versions prior to 2.14.3 and 2.12.12 contain a vulnerability where an unauthenticated MQTT client can send partial CONNECT packets that cause the server to retain large incomplete packets in memory. This leads to memory exhaustion before authentication completes. The issue is fixed in versions 2.14.3 and 2.12.12.
AI Analysis
Technical Summary
NATS Server, a messaging system server, has a vulnerability (CVE-2026-58210) in MQTT packet handling. Specifically, unauthenticated MQTT clients can send partial CONNECT packets that cause the server to hold large incomplete packets in memory while waiting for the full packet length, leading to pre-authentication memory exhaustion. This flaw affects versions prior to 2.14.3 and 2.12.12 and has been addressed in those fixed versions.
Potential Impact
An unauthenticated attacker can cause the NATS Server to consume excessive memory resources by sending incomplete MQTT CONNECT packets. This can lead to denial of service conditions due to memory exhaustion before the client is authenticated. There are no known exploits in the wild at this time.
Mitigation Recommendations
Upgrade NATS Server to version 2.14.3 or later, or 2.12.12 or later, where this issue has been fixed. Since a patch is available, applying the official fix is the recommended remediation.
NATS Server: MQTT partial CONNECT packets can exhaust pre-auth memory (CVE-2026-58210)
Description
NATS Server versions prior to 2.14.3 and 2.12.12 contain a vulnerability where an unauthenticated MQTT client can send partial CONNECT packets that cause the server to retain large incomplete packets in memory. This leads to memory exhaustion before authentication completes. The issue is fixed in versions 2.14.3 and 2.12.12.
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
NATS Server, a messaging system server, has a vulnerability (CVE-2026-58210) in MQTT packet handling. Specifically, unauthenticated MQTT clients can send partial CONNECT packets that cause the server to hold large incomplete packets in memory while waiting for the full packet length, leading to pre-authentication memory exhaustion. This flaw affects versions prior to 2.14.3 and 2.12.12 and has been addressed in those fixed versions.
Potential Impact
An unauthenticated attacker can cause the NATS Server to consume excessive memory resources by sending incomplete MQTT CONNECT packets. This can lead to denial of service conditions due to memory exhaustion before the client is authenticated. There are no known exploits in the wild at this time.
Mitigation Recommendations
Upgrade NATS Server to version 2.14.3 or later, or 2.12.12 or later, where this issue has been fixed. Since a patch is available, applying the official fix is the recommended remediation.
Technical Details
- Gcve Source
- db.gcve.eu
- Osv Id
- UBUNTU-CVE-2026-58210
- Osv Schema Version
- 1.7.0
- Ecosystems
- ["Ubuntu:24.04:LTS","Ubuntu:25.10","Ubuntu:Pro:26.04:LTS"]
- Cvss Version
- 3.1
- State
- PUBLISHED
Threat ID: 6a58b46268715ace43d6e793
Added to database: 07/16/2026, 10:37:22 UTC
Last enriched: 09/08/2026, 15:19:57 UTC
Last updated: 09/10/2026, 20:22:41 UTC
Views: 23
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