← Vulnerability feed

Vulnerability record · CVE-2021-34863 · published 25 October 2021

CVE-2021-34863: Dlink dap-2020 firmware stack-based buffer overflow vulnerability

Dlink · Dap 2020 Firmware

This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of D-Link DAP-2020 1.01rc001 routers. Authentication is not required to exploit this vulnerability. The specific flaw exists within the handling of the var:page parameter provided to the webproc endpoint. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-13271.

8.8 CVSS 3.1 High EPSS 1.5% · top 27.0% CWE-121 · Stack-based buffer overflow
8.8CVSS 3.1 base score, v2 5.8
1.5%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
4References
17 Jun 2026Last modified by NVD

Description

This vulnerability allows network-adjacent attackers to execute arbitrary code on affected installations of D-Link DAP-2020 1.01rc001 routers. Authentication is not required to exploit this vulnerability. The specific flaw exists within the handling of the var:page parameter provided to the webproc endpoint. The issue results from the lack of proper validation of the length of user-supplied data prior to copying it to a fixed-length stack-based buffer. An attacker can leverage this vulnerability to execute code in the context of root. Was ZDI-CAN-13271.

CVSS:3.1/AV:A/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://supportannouncement.us.dlink.com/announcement/publication.aspx?name=SAP10201 PatchVendor Advisory
https://www.zerodayinitiative.com/advisories/ZDI-21-979/ Third Party AdvisoryVDB Entry
https://supportannouncement.us.dlink.com/announcement/publication.aspx?name=SAP10201 PatchVendor Advisory
https://www.zerodayinitiative.com/advisories/ZDI-21-979/ Third Party AdvisoryVDB Entry

Track CVE-2021-34863 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

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

8.8CVE-2023-32146Dlink dap-2020 firmware stack-based buffer overflow vulnerabilityD-Link DAP-1360 Multiple Parameters Stack-Based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows network-adjacent attac…EPSS 1.1%8.8CVE-2023-32144Dlink dap-1360 firmware stack-based buffer overflow vulnerabilityD-Link DAP-1360 webproc COMM_MakeCustomMsg Stack-based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows network-adjacen…EPSS 1.0%8.8CVE-2023-32145Dlink dap-1360 firmware hard-coded password vulnerabilityD-Link DAP-1360 Hardcoded Credentials Authentication Bypass Vulnerability. This vulnerability allows network-adjacent attackers to bypass authenticat…EPSS 0.92%8.8CVE-2023-32143Dlink dap-1360 firmware vulnerabilityD-Link DAP-1360 webupg UPGCGI_CheckAuth Numeric Truncation Remote Code Execution Vulnerability. This vulnerability allows network-adjacent attackers …EPSS 1.1%8.8CVE-2023-32141Dlink dap-1360 firmware stack-based buffer overflow vulnerabilityD-Link DAP-1360 webproc WEB_DisplayPage Stack-based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows network-adjacent a…EPSS 1.1%8.8CVE-2023-32139Dlink dap-1360 firmware stack-based buffer overflow vulnerabilityD-Link DAP-1360 webproc Stack-based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows network-adjacent attackers to exec…EPSS 1.0%8.8CVE-2023-32142Dlink dap-1360 firmware stack-based buffer overflow vulnerabilityD-Link DAP-1360 webproc var:page Stack-based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows network-adjacent attacker…EPSS 1.1%8.8CVE-2023-32138Dlink dap-1360 firmware heap-based buffer overflow vulnerabilityD-Link DAP-1360 webproc Heap-based Buffer Overflow Remote Code Execution Vulnerability. This vulnerability allows network-adjacent attackers to execu…EPSS 0.93%

Source: NIST National Vulnerability Database (record CVE-2021-34863), CISA KEV, FIRST EPSS (scores of 2026-10-03). This page is refreshed as NVD updates the record.