TI-2021-16780 Aliases CVE-2021-39509 GHSA-xvjj-gv4g-2h8h

An issue was discovered in D-Link DIR-816 DIR-816A2_FWv1.10CNB05_R1B011D88210 The HTTP…

MEDIUM 50CWE-77Published 2021-08-24 · Updated 2024-08-04

Key facts

Attack vector: Network
Privileges required: None
User interaction: None
Attack complexity: Low
Impact type: Code execution
Confidentiality · integrity · availability: High · High · High
Fix status: No fix listed

Attack profile from CVSS 3.1 · NVD. Fix status from CNA. Impact type from CWE-77.

Summary

An issue was discovered in D-Link DIR-816 DIR-816A2_FWv1.10CNB05_R1B011D88210 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.

Why it matters now

EPSS 0.05098 92nd percentileScored 2026-11-07

Public exploit Yes 1 exploit referenceTagged by NVD

Fix No fix listed No fixed version in the sources yet

SSVC decision points

Not available: CISA has not published SSVC decision points for this record.

Affected products

Vendor	Product	Affected versions	Fixed in	Status	Source
—	—	all versions	—	No fix listed	CNA

— Vendor— Affected all versions Fixed in — No fix listed CNA

CPE configurations NVD · 2

CPE	Versions	Role	Vendor
cpe:2.3:o:dlink:dir-816_firmware:1.10cnb05_r1b011d88210:::::::*	1.10cnb05_r1b011d88210	Vulnerable	D-Link Japan K.K.
cpe:2.3:h:dlink:dir-816:a2:::::::*	a2	Running on	D-Link Japan K.K.

cpe:2.3:o:dlink:dir-816_firmware:1.10cnb05_r1b011d88210:*:*:*:*:*:*:* Versions 1.10cnb05_r1b011d88210 Vulnerable ·D-Link Japan K.K.
cpe:2.3:h:dlink:dir-816:a2:*:*:*:*:*:*:* Versions a2 Running on ·D-Link Japan K.K.

Remediation

No fixed version listed by the sources yet.

Timeline

2026-10-02 Threatist record created from CVE-2021-39509
2026-10-03 Alias added: GHSA-xvjj-gv4g-2h8h

References

Exploit 1

https://github.com/doudoudedi/main-DIR-816_A2_Command-injection/blob/main/injection.md

Advisory 2

TI-2025-28895 An issue D-Link DIR-816-A2 DIR-816A2_FWv1.10CNB05_R1B011D88210 allows a remote attacker… CVSS 3.1CRITICAL 9.8
TI-2024-38028 An access control issue in the component formDMZ.cgi of D-Link… CVSS 3.1CRITICAL 9.8
TI-2023-09977 Command Injection vulnerability in D-Link Dir 816 with firmware version… CVSS 3.1CRITICAL 9.8
TI-2022-20974 D-Link DIR-816 A2 1.10 B05 was discovered to contain a stack overflow via the pskValue… CVSS 3.1CRITICAL 9.8
TI-2022-20973 D-Link DIR-816 A2 1.10 B05 was discovered to contain a stack overflow via the… CVSS 3.1CRITICAL 9.8
TI-2022-20972 D-Link DIR-816 A2 1.10 B05 was discovered to contain a stack overflow via the pskValue… CVSS 3.1CRITICAL 9.8

See all 72 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences