CVE intelligence and bounded remediation

CVE-2021-27250 — Dlink Dap-2020 Firmware security vulnerability

Medium CVSS 6.5

This vulnerability allows network-adjacent attackers to disclose sensitive information on affected installations of D-Link DAP-2020 v1.01rc001 Wi-Fi access points. Authentication is not required to exploit this vulnerability. The specific flaw exists within the processing of CGI scripts. When parsing the errorpage request parameter, the process does not properly validate a user-supplied path prior to using it in file operations. An attacker can leverage this vulnerability to disclose stored credentials, leading to further compromise. Was ZDI-CAN-11856.

Severity
Medium
CVSS
6.5 (3.1)
Published
2021-04-14
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-73

Affected products

  • dlink / dap-2020_firmware / 1.01

Matched remediation archetype

Path traversal, unsafe upload, and file handling

This catalog composition supplies bounded fallback guidance. Explicitly reviewed curated workflows load with the complete record below.

Check exposure

  • Trace untrusted filenames, archive entries, URLs, and path segments into read, write, include, extraction, and upload operations.
  • Identify filesystem roots, mount permissions, symbolic-link behavior, archive handling, and whether uploaded content is web-accessible or executable.
  • Review canonicalization and containment checks across supported operating systems and storage backends.

Remediate safely

  • Generate server-side storage identifiers and resolve paths beneath a fixed root using filesystem-aware containment checks.
  • Reject absolute, parent-relative, alternate-separator, device, link, and archive entries that escape the intended root.
  • Store uploads outside executable or served paths, validate type and size, and use private atomic temporary files.

Authoritative sources

Complete CVE record and remediation plan

The detailed catalog view below loads this exact record, its source evidence, and the full seven-phase agentic change plan.