Improper input validation in Linuxfoundation Nats-Server
CVE-2026-33218
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.
Vulnerability class: Drupalgeddon 2 (CVE-2018-7600)
Published · last modified .
CVSS v3 metric
CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.
EPSS exploit prediction
EPSS: 0.008 (56.3th percentile), scored .
Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 56th percentile — 56.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.
EPSS over last 30 days · oldest: 0.006 · newest: 0.008 · change: +0.002
Affected products
- Linuxfoundation Nats-Server
- Nats-Io Nats-Server — versions < < 2.11.15, >= 2.12.0-RC.1, < 2.12.6
Weakness classification (CWE)
References
- github.com/nats-io/nats-server/security/advisories/GHSA-vprv-35vv-q339 (Mitigation, Vendor Advisory)
- advisories.nats.io/CVE/secnote-2026-10.txt (Mitigation, Vendor Advisory)
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
- 0b0ca135-0b70-47e7-9f44-1890c2a1c46c
Frequently asked questions
- What is CVE-2026-33218?
- CVE-2026-33218 is a high-severity vulnerability in Linuxfoundation Nats-Server, classified under Improper Input Validation. CVSS score: 7.5/10. Published 2026-03-25.
- How severe is CVE-2026-33218?
- High severity. CVSS v3 base score is 7.5 out of 10.