CVE-2021-47741Public exploitNetwork attack vector

Privilege escalation via exposed super-user password

Published Dec 31, 2025 · Updated Dec 31, 2025

Privilege escalation in ZBL EPON ONU Broadband Router V100R001 allows remote authenticated users to obtain super-user access. The configuration backup endpoint and system_password.asp page return the super account password to a limited administrative session without enforcing the super-user privilege boundary. A limited admin can then authenticate as super and use additional privileged management functions; the disclosed evidence does not establish unauthenticated reachability.

CVSS severity8.7
High
EPSS probability0.28%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Privilege escalation in ZBL EPON ONU Broadband Router V100R001 allows remote authenticated users to obtain super-user access. The configuration backup endpoint and system_password.asp page return the super account password to a limited administrative session without enforcing the super-user privilege boundary. A limited admin can then authenticate as super and use additional privileged management functions; the disclosed evidence does not establish unauthenticated reachability.

The record

CVE
CVE-2021-47741
Published
Dec 31, 2025
Updated
Dec 31, 2025
Vendor
Zhejiang BC&TV Technology Co., Ltd.
Product
ZBL EPON ONU Broadband Router
Classifications
CWE-522, T1190
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Dec 31, 2025CVE publishedPublication date reported by the CVE source.
  2. Dec 31, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Zhejiang BC&TV Technology Co., Ltd. · ZBL EPON ONU Broadband Routerversion=1.0

Published CVSS scores

8.7VulnCheckCVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
7.5VulnCheckCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-522Insufficiently Protected Credentials
T1190Exploit Public-Facing Application

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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