CVE-2021-28839

Severity: high (CVSS 7.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.4% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2021-08-10 · updated 2026-06-17
Weakness: CWE-476

Description

Null Pointer Dereference vulnerability exists in D-Link DAP-2310 2.07.RC031, DAP-2330 1.07.RC028, DAP-2360 2.07.RC043, DAP-2553 3.06.RC027, DAP-2660 1.13.RC074, DAP-2690 3.16.RC100, DAP-2695 1.17.RC063, DAP-3320 1.01.RC014 and DAP-3662 1.01.RC022 in the upload_certificate function of sbin/httpd binary. When the binary handle the specific HTTP GET request, the strrchr in the upload_certificate function would take NULL as first argument, and incur the NULL pointer dereference vulnerability.

Affected products

Dlink Dap-2310 Firmware: 2.0.7.rc031
Dlink Dap-2330 Firmware: 1.07.rc028
Dlink Dap-2360 Firmware: 2.07.rc043
Dlink Dap-2553 Firmware: 3.06.rc027
Dlink Dap-2660 Firmware: 1.13.rc074
Dlink Dap-2690 Firmware: 3.16.rc100
D-Link DAP-2695: 1.17.rc063
Dlink Dap-3320 Firmware: 1.01.rc014
Dlink Dap-3662 Firmware: 1.01.rc022

References

https://github.com/zyw-200/EQUAFL/blob/main/dlink-email-cve.pdf
https://github.com/zyw-200/EQUAFL/blob/main/dlink-email-cve2.pdf
https://www.dlink.com/en/security-bulletin/
https://github.com/zyw-200/EQUAFL/blob/main/dlink-email-cve.pdf
https://github.com/zyw-200/EQUAFL/blob/main/dlink-email-cve2.pdf
https://www.dlink.com/en/security-bulletin/

Get alerted when CVE-2021-28839 or the next vulnerability affects your stack