CVE intelligence and bounded remediation

CVE-2021-29448 — Pi-hole is a Linux network-level advertisement and Internet tracker blocking application

High CVSS 8.8

Pi-hole is a Linux network-level advertisement and Internet tracker blocking application. The Stored XSS exists in the Pi-hole Admin portal, which can be exploited by the malicious actor with the network access to DNS server. See the referenced GitHub security advisory for patch details.

Severity
High
CVSS
8.8 (3.1)
Published
2021-04-15
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-79

Affected products

  • pi-hole / ftldns / 5.7
  • pi-hole / pi-hole / 5.2.4
  • pi-hole / web_interface

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

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