What is CVE-2026-33280?

CVE-2026-33280 is a critical-severity vulnerability in Buffalo Fs-M1266, classified under Hidden Functionality. CVSS score: 9.8/10. Published 2026-03-27.

How severe is CVE-2026-33280?

Critical severity. CVSS v3 base score is 9.8 out of 10.

Vulnerability in Buffalo Fs-M1266

CVE-2026-33280

Hidden functionality issue exists in BUFFALO Wi-Fi router products, which may allow an attacker to gain access to the product’s debugging functionality, resulting in the execution of arbitrary OS commands.

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

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.007 (50.1th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 50th percentile — 50.1% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.004 · newest: 0.007 · change: +0.003

Affected products

Weakness classification (CWE)

CWE-912 — Hidden Functionality

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-2026-33280?: CVE-2026-33280 is a critical-severity vulnerability in Buffalo Fs-M1266, classified under Hidden Functionality. CVSS score: 9.8/10. Published 2026-03-27.
How severe is CVE-2026-33280?: Critical severity. CVSS v3 base score is 9.8 out of 10.