What is CVE-2021-27156?

CVE-2021-27156 is a critical-severity vulnerability in Fiberhome Hg6245d, classified under Use of Hard-coded Credentials. CVSS score: 9.8/10. Published 2021-02-10.

How severe is CVE-2021-27156?

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

Vulnerability in Fiberhome Hg6245d

CVE-2021-27156

An issue was discovered on FiberHome HG6245D devices through RP2613. The web daemon contains credentials for an ISP that equal the last part of the MAC address of the br0 interface.

Published 2021-02-10 · 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: 0.150 (96.6th percentile), scored 2026-09-29.

Moderate probability of exploitation in the next 30 days — watch for active exploitation reports. 97th percentile — 96.6% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.145 · newest: 0.150 · change: +0.005

Affected products

Weakness classification (CWE)

CWE-798 — Use of Hard-coded Credentials

References

pierrekim.github.io/blog/2021-01-12-fiberhome-ont-0day-vulnerabilities.html (Exploit, Third Party Advisory)

Frequently asked questions

What is CVE-2021-27156?: CVE-2021-27156 is a critical-severity vulnerability in Fiberhome Hg6245d, classified under Use of Hard-coded Credentials. CVSS score: 9.8/10. Published 2021-02-10.
How severe is CVE-2021-27156?: Critical severity. CVSS v3 base score is 9.8 out of 10.