CVE-2026-29785
HIGHNATS Server panic via malicious compression on leafnode port
Title source: cnaDescription
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.
References (3)
Core 3
Core References
X_Refsource_Confirm x_refsource_confirm
https://github.com/nats-io/nats-server/security/advisories/GHSA-52jh-2xxh-pwh6
X_Refsource_Misc x_refsource_misc
https://github.com/nats-io/nats-server/commit/a1488de6f2ba6e666aef0f9cce0016f7f167d6a8
X_Refsource_Misc x_refsource_misc
https://advisories.nats.io/CVE/secnote-2026-04.txt
Scores
CVSS v3
7.5
EPSS
0.0039
EPSS Percentile
30.2%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
yes
Technical Impact
partial
Details
CWE
CWE-476
Status
published
Products (5)
linuxfoundation/nats-server
< 2.11.14
nats-io/nats-server
0Go
nats-io/nats-server
0 - 2.11.14Go
nats-io/nats-server
< 2.11.14
nats-io/nats-server
>= 2.12.0-RC.1, < 2.12.5
Published
Mar 25, 2026
Tracked Since
Mar 26, 2026