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No exploitation reportedFix available

CVE-2021-34863

No exploitation reported by the sources we read.

  • Published2021-10-25
  • WeaknessCWE-121

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

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.

Timeline

dates in UTC
  1. 2021-10-2517:15CVE publishedNVD

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2021-34863?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2021-34863?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Dlink dap-2020 firmwareversion to verify
BranchAffectedFixed in
1.1≤ 1.01no fix published

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

Advisories and patches

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
none listed
PoC-in-GitHub

Sources

  • NVDCVSS 3.18.8read 2026-10-23
  • CNACVSS 3.08.8read 2026-10-23
  • NVDCVSS 2.05.8read 2026-10-23
  • CNAweakness (CWE)CWE-121read 2026-10-23
  • FIRST EPSSEPSS score1.5 %2026-10-22

Technical details

CVSS v3 Vector
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
2021-10-25
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2021-34863?

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.

Is CVE-2021-34863 actively exploited?

Active exploitation of CVE-2021-34863 has not been confirmed. Its EPSS score was 1.5% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2021-34863?

CVE-2021-34863 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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