What is CVE-2026-27650?

CVE-2026-27650 is a critical-severity vulnerability in Buffalo Fs-M1266, classified under OS Command Injection. CVSS score: 9.8/10. Published 2026-03-27.

How severe is CVE-2026-27650?

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

RCE in Buffalo Fs-M1266

CVE-2026-27650

OS Command Injection vulnerability exists in BUFFALO Wi-Fi router products. If this vulnerability is exploited, an arbitrary OS command may be executed on the products.

Vulnerability class: Command Injection (OS Command Injection)

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: 0.014 (72.3th percentile), scored 2026-09-29.

Low probability of exploitation in the next 30 days, but still tracked. 72nd percentile — 72.3% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.009 · newest: 0.014 · change: +0.005

Affected products

Weakness classification (CWE)

CWE-78 — OS Command Injection

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-2026-27650?: CVE-2026-27650 is a critical-severity vulnerability in Buffalo Fs-M1266, classified under OS Command Injection. CVSS score: 9.8/10. Published 2026-03-27.
How severe is CVE-2026-27650?: Critical severity. CVSS v3 base score is 9.8 out of 10.