CVE-2021-28152

CRITICALNVD 9.89.8—Elevated

9.8

Hongdian H8922 3.0.5 devices have an undocumented feature that allows access to a shell as a superuser. To connect, the telnet service is used on port 5188 with the default credentials of root:superzxmn.

CVSS v3: 9.8
EG Score: 9.8(medium)
EPSS: 97.3%
KEV: Not listed

Published

May 6, 2021

Last Modified

November 21, 2024

Advisory Details (1)

Auto-updated May 26, 2026

No patch confirmed yet.

generic

SSD Advisory – Hongdian H8922 Multiple Vulnerabilities - SSD Secure Disclosure

https://ssd-disclosure.com/ssd-advisory-hongdian-h8922-multiple-vulnerabilities/

Weakness Classification(2)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 9× in last 7d / 15× in last 30d)

Every time one of our enrichment pipelines (NVD, MITRE cvelistV5, EPSS, CISA KEV, GHSA, OSV, vendor advisories) ran against this CVE. Most recent first.

2026-06-02 20:11 UTCepss_batch
2026-06-02 20:11 UTCepss_batch
2026-06-02 20:11 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 22:29 UTCepss_batch
2026-05-31 00:15 UTCepss_batch
2026-05-29 13:42 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-28 13:43 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-27 13:39 UTCepss_batch
2026-05-26 16:59 UTCEG score recompute
2026-05-26 16:59 UTCGHSA enrichment
2026-05-26 07:17 UTCepss_batch
2026-05-26 07:17 UTCepss_batch

Frequently asked(5)

What is CVE-2021-28152?

CVE-2021-28152 is a critical vulnerability published on May 6, 2021. Hongdian H8922 3.0.5 devices have an undocumented feature that allows access to a shell as a superuser. To connect, the telnet service is used on port 5188 with the default credentials of root:superzxmn.

When was CVE-2021-28152 disclosed?

CVE-2021-28152 was first published in the National Vulnerability Database on May 6, 2021, with the most recent update on November 21, 2024. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.

Is CVE-2021-28152 actively exploited?

CVE-2021-28152 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 97.3% percentile likelihood of exploitation in the next 30 days — higher percentiles indicate greater predicted risk.

What is the CVSS score of CVE-2021-28152?

CVE-2021-28152 has a CVSS v3 base score of 9.8 (NVD).

How do I remediate CVE-2021-28152?

Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2021-28152, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

See which npm, PyPI, Go, and Maven packages are affected by CVE-2021-28152

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CVE-2021-28152

📅 Published

🔄 Last Modified

📋 Advisory Details (1)

SSD Advisory – Hongdian H8922 Multiple Vulnerabilities - SSD Secure Disclosure

Weakness Classification(2)

Data Freshness Timeline

❓ Frequently asked(5)

Dependency Blast Radius

Is Your Infrastructure Affected by CVE-2021-28152?

🔗 Related CVEs(same CWE)

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Published

Last Modified

Advisory Details (1)

Frequently asked(5)

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