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Vulnerability record · CVE-2021-47741 · published 31 December 2025

CVE-2021-47741: Insufficiently protected credentials vulnerability

ZBL EPON ONU Broadband Router V100R001 contains a privilege escalation vulnerability that allows limited administrative users to elevate access by sending requests to configuration endpoints. Attackers can exploit the vulnerability by accessing the configuration backup or password page to disclose the super user password and gain additional privileged functionalities.

8.7 CVSS 4.0 High EPSS 0.29% · top 81.0% CWE-522 · Insufficiently protected credentials Deferred
8.7CVSS 4.0 base score
0.29%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
5References
17 Jun 2026Last modified by NVD

Description

ZBL EPON ONU Broadband Router V100R001 contains a privilege escalation vulnerability that allows limited administrative users to elevate access by sending requests to configuration endpoints. Attackers can exploit the vulnerability by accessing the configuration backup or password page to disclose the super user password and gain additional privileged functionalities.

CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:

References

LinkTags
http://www.zblchina.com
https://web.archive.org/web/20211220094023/http://www.wd-thailand.com/
https://www.exploit-db.com/exploits/49737
https://www.vulncheck.com/advisories/zbl-epon-onu-broadband-router-vr-privilege-escalation-via-configuration-endpoint
https://www.zeroscience.mk/en/vulnerabilities/ZSL-2021-5647.php

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Source: NIST National Vulnerability Database (record CVE-2021-47741), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.