CVE-2021-47741
CVE-2021-47741 is a high-severity vulnerability with a CVSS 3.x base score of 7.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-522.
Key facts
- Severity: High (CVSS 3.x base score 7.5)
- CVSS v4: 8.7
- EPSS exploit prediction: 0% (16th percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2025-206085
- Weakness: CWE-522
- Published:
- Last modified:
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.
Frequently asked questions
- What is CVE-2021-47741?
- 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.
- How severe is CVE-2021-47741?
- CVE-2021-47741 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity none, and availability none.
- Is CVE-2021-47741 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (16th percentile), an estimate of the probability of exploitation in the next 30 days.
- How do I fix CVE-2021-47741?
- Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
- Does CVE-2021-47741 have an EU (EUVD) identifier?
- Yes. CVE-2021-47741 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2025-206085.
- When was CVE-2021-47741 published?
- CVE-2021-47741 was published on 2025-12-31 and last updated on 2026-06-17.
References
- 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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