CVE-2026-33249
MEDIUMNATS: Message tracing can be redirected to arbitrary subject
Title source: cnaDescription
NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Starting in version 2.11.0 and prior to versions 2.11.15 and 2.12.6, a valid client which uses message tracing headers can indicate that the trace messages can be sent to an arbitrary valid subject, including those to which the client does not have publish permission. The payload is a valid trace message and not chosen by the attacker. Versions 2.11.15 and 2.12.6 contain a fix. No known workarounds are available.
References (2)
Core 2
Core References
X_Refsource_Confirm x_refsource_confirm
https://github.com/nats-io/nats-server/security/advisories/GHSA-8m2x-3m6q-6w8j
X_Refsource_Misc x_refsource_misc
https://advisories.nats.io/CVE/secnote-2026-15.txt
Scores
CVSS v3
4.3
EPSS
0.0001
EPSS Percentile
1.3%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:L/A:N
CISA SSVC
Vulnrichment
Exploitation
none
Automatable
no
Technical Impact
partial
Details
CWE
CWE-863
Status
published
Products (4)
linuxfoundation/nats-server
2.11.0 - 2.11.15
nats-io/nats-server
2.11.0 - 2.11.15Go
nats-io/nats-server
>= 2.11.0, < 2.11.15
nats-io/nats-server
>= 2.12.0-preview.1, < 2.12.6
Published
Mar 25, 2026
Tracked Since
Mar 26, 2026