How severe is CVE-2021-28152?

CVE-2021-28152 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2021-28152 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2021-28152?

CVE-2021-28152 affects Hongdian H8922 Firmware. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2021-28152?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2021-28152 published?

CVE-2021-28152 was published on 2021-05-06 and last updated on 2026-06-17.

CVE-2021-28152

CVE-2021-28152 is a critical-severity vulnerability in Hongdian H8922 Firmware with a CVSS 3.x base score of 9.8. 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-287.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 5% (91st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-287
Affected product: Hongdian H8922 Firmware
Published: 2021-05-06
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2021-28152?: 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.
How severe is CVE-2021-28152?: CVE-2021-28152 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2021-28152 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2021-28152?: CVE-2021-28152 affects Hongdian H8922 Firmware. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2021-28152?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2021-28152 published?: CVE-2021-28152 was published on 2021-05-06 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:o:hongdian:h8922_firmware:3.0.5:*:*:*:*:*:*:*

More vulnerabilities in Hongdian H8922 Firmware

CVE-2021-28151 — High (CVSS 8.8): Hongdian H8922 3.0.5 devices allow OS command injection via shell metacharacters into the ip-address (aka Destination)…
CVE-2021-28149 — Medium (CVSS 6.5): Hongdian H8922 3.0.5 devices allow Directory Traversal. The /log_download.cgi log export handler does not validate user…
CVE-2021-28150 — Medium (CVSS 5.5): Hongdian H8922 3.0.5 devices allow the unprivileged guest user to read cli.conf (with the administrator password and…

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