CVE intelligence and bounded remediation

CVE-2020-5797 — Tp-Link Archer C9 Firmware security vulnerability

Medium CVSS 6.1

UNIX Symbolic Link (Symlink) Following in TP-Link Archer C9(US)_V1_180125 firmware allows an unauthenticated actor, with physical access and network access, to read sensitive files and write to a limited set of files after plugging a crafted USB drive into the router.

Severity
Medium
CVSS
6.1 (3.1)
Published
2020-11-21
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-59

Affected products

  • tp-link / archer_c9_firmware / 180125

Matched remediation archetype

Path traversal, unsafe upload, and file handling

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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

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