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Vulnerability record · CVE-2021-39510 · published 24 August 2021

CVE-2021-39510: Dlink dir-816 firmware command injection vulnerability

Dlink · Dir 816 Firmware

An issue was discovered in D-Link DIR816_A1_FW101CNB04 750m11ac wireless router, The HTTP request parameter is used in the handler function of /goform/form2userconfig.cgi route, which can construct the user name string to delete the user function. This can lead to command injection through shell metacharacters.

9.8 CVSS 3.1 Critical EPSS 8.6% · top 5.1% CWE-77 · Command injection
9.8CVSS 3.1 base score, v2 7.5
8.6%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
6References, 2 tagged exploit
17 Jun 2026Last modified by NVD

Description

An issue was discovered in D-Link DIR816_A1_FW101CNB04 750m11ac wireless router, The HTTP request parameter is used in the handler function of /goform/form2userconfig.cgi route, which can construct the user name string to delete the user function. This can lead to command injection through shell metacharacters.

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/doudoudedi/main-DIR-816_A1_Command-injection Third Party Advisory
https://github.com/doudoudedi/main-DIR-816_A1_Command-injection/blob/main/injection_A1.md ExploitThird Party Advisory
https://www.dlink.com/en/security-bulletin/ Vendor Advisory
https://github.com/doudoudedi/main-DIR-816_A1_Command-injection Third Party Advisory
https://github.com/doudoudedi/main-DIR-816_A1_Command-injection/blob/main/injection_A1.md ExploitThird Party Advisory
https://www.dlink.com/en/security-bulletin/ Vendor Advisory

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

9.8CVE-2025-45931Dlink dir-816 firmware command injection vulnerabilityAn issue D-Link DIR-816-A2 DIR-816A2_FWv1.10CNB05_R1B011D88210 allows a remote attacker to execute arbitrary code via system() function in the bin/go…EPSS 0.96%9.8CVE-2024-57684Dlink dir-816 firmware incorrect default permissions vulnerabilityAn access control issue in the component formDMZ.cgi of D-Link 816A2_FWv1.10CNB05_R1B011D88210 allows unauthenticated attackers to set the DMZ servic…EPSS 14%9.8CVE-2023-24331Dlink dir-816 firmware command injection vulnerabilityCommand Injection vulnerability in D-Link Dir 816 with firmware version DIR-816_A2_v1.10CNB04 allows attackers to run arbitrary commands via the urlA…EPSS 2.1%9.8CVE-2024-24321Dlink dir-816 firmware command injection vulnerabilityAn issue in Dlink DIR-816A2 v.1.10CNB05 allows a remote attacker to execute arbitrary code via the wizardstep4_ssid_2 parameter in the sub_42DA54 fun…EPSS 1.9%9.8CVE-2023-39637Dlink dir-816 firmware command injection vulnerabilityD-Link DIR-816 A2 1.10 B05 was discovered to contain a command injection vulnerability via the component /goform/Diagnosis.EPSS 2.1%9.8CVE-2022-43002Dlink dir-816 firmware out-of-bounds write vulnerabilityD-Link DIR-816 A2 1.10 B05 was discovered to contain a stack overflow via the wizardstep54_pskpwd parameter at /goform/form2WizardStep54.EPSS 1.2%9.8CVE-2022-43003Dlink dir-816 firmware out-of-bounds write vulnerabilityD-Link DIR-816 A2 1.10 B05 was discovered to contain a stack overflow via the pskValue parameter in the setRepeaterSecurity function.EPSS 1.2%9.8CVE-2022-43000Dlink dir-816 firmware out-of-bounds write vulnerabilityD-Link DIR-816 A2 1.10 B05 was discovered to contain a stack overflow via the wizardstep4_pskpwd parameter at /goform/form2WizardStep4.EPSS 1.2%

Source: NIST National Vulnerability Database (record CVE-2021-39510), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.