CVE-2026-29785
NATS Server panic via malicious compression on leafnode port
CVSS Score
7.5
EPSS Score
0.1%
EPSS Percentile
23th
NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.14 and 2.12.5, if the nats-server has the "leafnode" configuration enabled (not default), then anyone who can connect can crash the nats-server by triggering a panic. This happens pre-authentication and requires that compression be enabled (which it is, by default, when leafnodes are used). Versions 2.11.14 and 2.12.5 contain a fix. As a workaround, disable compression on the leafnode port.
| CWE | CWE-476 |
| Vendor | nats-io |
| Product | nats-server |
| Published | Mar 25, 2026 |
| Last Updated | Mar 28, 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
< 2.11.14 >= 2.12.0-RC.1, < 2.12.5