CVE intelligence and bounded remediation

CVE-2021-3275 — Tp-Link Td-W9977 Firmware security vulnerability

Medium CVSS 6.1

Unauthenticated stored cross-site scripting (XSS) exists in multiple TP-Link products including WIFI Routers (Wireless AC routers), Access Points, ADSL + DSL Gateways and Routers, which affects TD-W9977v1, TL-WA801NDv5, TL-WA801Nv6, TL-WA802Nv5, and Archer C3150v2 devices through the improper validation of the hostname. Some of the pages including dhcp.htm, networkMap.htm, dhcpClient.htm, qsEdit.htm, and qsReview.htm and use this vulnerable hostname function (setDefaultHostname()) without sanitization.

Severity
Medium
CVSS
6.1 (3.1)
Published
2021-03-26
CISA KEV
Not currently listed
Ecosystem
operating-system
Weaknesses
CWE-79

Affected products

  • tp-link / td-w9977_firmware / v1_0.1.0_0.9.1_up_boot(161123)_2016-11-23_15.36.15
  • tp-link / tl-wa801nd_firmware / v5_us_0.9.1_3.16_up_boot[170905-rel56404]
  • tp-link / tl-wa801n_firmware / v6_eu_0.9.1_3.16_up_boot[200116-rel61815]
  • tp-link / tl-wr802n_firmware / v4_us_0.9.1_3.17_up_boot[200421-rel38950]
  • tp-link / archer-c3150_firmware / v2_170926

Matched remediation archetype

Cross-site scripting and unsafe browser output

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

Check exposure

  • Trace reflected, stored, and DOM-derived untrusted values into HTML, attributes, URLs, styles, scripts, and client-side template sinks.
  • Identify affected origins, authenticated user roles, sensitive browser capabilities, and where content is shared across tenants.
  • Review framework escaping, rich-text sanitization, legacy templates, and client-side rendering paths.

Remediate safely

  • Use context-aware framework output encoding and safe DOM APIs; keep untrusted data out of executable contexts.
  • Sanitize intentionally supported markup with a maintained allowlist policy and validate URLs and attributes separately.
  • Update affected rendering components and add tests for every output context using inert sentinel markup.

Authoritative sources

Complete CVE record and remediation plan

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