What is CVE-2026-33366?

CVE-2026-33366 is a medium-severity vulnerability in Buffalo Fs-M1266, classified under Missing Authentication for Critical Function. CVSS score: 5.3/10. Published 2026-03-27.

How severe is CVE-2026-33366?

Medium severity. CVSS v3 base score is 5.3 out of 10.

Auth bypass in Buffalo Fs-M1266

CVE-2026-33366

Missing authentication for critical function vulnerability in BUFFALO Wi-Fi router products may allow an attacker to forcibly reboot the product without authentication.

Vulnerability class: Broken Authentication

Published 2026-03-27 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 5.3 (Medium). Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L.

EPSS exploit prediction

EPSS: 0.005 (43.8th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 44th percentile — 43.8% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.003 · newest: 0.005 · change: +0.002

Affected products

Weakness classification (CWE)

CWE-306 — Missing Authentication for Critical Function

References

www.buffalo.jp/news/detail/20260323-01.html (Vendor Advisory)
jvn.jp/en/jp/JVN83788689/ (Third Party Advisory)

Frequently asked questions

What is CVE-2026-33366?: CVE-2026-33366 is a medium-severity vulnerability in Buffalo Fs-M1266, classified under Missing Authentication for Critical Function. CVSS score: 5.3/10. Published 2026-03-27.
How severe is CVE-2026-33366?: Medium severity. CVSS v3 base score is 5.3 out of 10.