CVE-2026-33218

moderate-risk
Published 2026-03-25

NATS-Server is a High-Performance server for NATS.io, a cloud and edge native messaging system. Prior to versions 2.11.15 and 2.12.6, a client which can connect to the leafnode port can crash the nats-server with a certain malformed message pre-authentication. Versions 2.11.15 and 2.12.6 contain a fix. As a workaround, disable leafnode support if not needed or restrict network connections to the leafnode port, if plausible without compromising the service offered.

Do I need to act?

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0.17% chance of exploitation
EPSS score — low exploit probability
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Not on CISA KEV list
No confirmed active exploitation reported to CISA
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Patch status unknown
Check vendor advisories for fix availability and mitigation guidance
7
CVSS 7.5/10 High
NETWORK / LOW complexity

Affected Products (1)

Affected Vendors

Linuxfoundation

References (2)

Mitigation https://advisories.nats.io/CVE/secnote-2026-10.txt
Mitigation https://github.com/nats-io/nats-server/security/advisories/GHSA-vprv-35vv-q339
32
/ 100
moderate-risk
Severity 26/34 · High
Exploitability 1/34 · Minimal
Exposure 5/34 · Minimal