CVE-2026-58210
NATS Server: MQTT partial CONNECT packets can exhaust pre-auth memory
CVSS Score
7.5
EPSS Score
0.7%
EPSS Percentile
50th
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 unauthenticated MQTT client could cause the server to retain large incomplete MQTT CONNECT packets before authentication completed, consuming server memory while the parser waited for the advertised MQTT packet length. This issue is fixed in versions 2.14.3 and 2.12.12.
| CWE | CWE-400 |
| Vendor | nats-io |
| Product | nats-server |
| Published | Jul 8, 2026 |
| Last Updated | Jul 9, 2026 |
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CVSS v3 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High
Affected Versions
nats-io / nats-server
< 2.12.12 >= 2.14.0-RC.1, < 2.14.3
References
github.com: https://github.com/nats-io/nats-server/security/advisories/GHSA-r72h-j7qq-v6qg github.com: https://github.com/nats-io/nats-server/commit/bce9ef39469e610aeddb819194ceb7f7edfc0861 github.com: https://github.com/nats-io/nats-server/commit/e016e47bbf70304945f2ae9dc397e4862adefaf5 github.com: https://github.com/nats-io/nats-server/releases/tag/v2.12.12 github.com: https://github.com/nats-io/nats-server/releases/tag/v2.14.3