CVE intelligence and bounded remediation

CVE-2021-20829 — Weseek Growi security vulnerability

Medium CVSS 6.1

Cross-site scripting vulnerability due to the inadequate tag sanitization in GROWI versions v4.2.19 and earlier allows remote attackers to execute an arbitrary script on the web browser of the user who accesses a specially crafted page.

Severity
Medium
CVSS
6.1 (3.1)
Published
2021-09-21
CISA KEV
Not currently listed
Ecosystem
software/application
Weaknesses
CWE-79

Affected products

  • weseek / growi

Matched remediation archetype

Cross-site scripting and unsafe browser output

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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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