CVE intelligence and bounded remediation
CVE-2021-39250 — Invisioncommunity Invision Power Board security vulnerability
Invision Community (aka IPS Community Suite or IP-Board) before 4.6.5.1 allows stored XSS, with resultant code execution, because an uploaded file can be placed in an IFRAME element within user-generated content. For code execution, the attacker can rely on the ability of an admin to install widgets, disclosure of the admin session ID in a Referer header, and the ability of an admin to use the templating engine (e.g., Edit HTML).
- Severity
- Medium
- CVSS
- 5.4 (3.1)
- Published
- 2021-08-17
- CISA KEV
- Not currently listed
- Ecosystem
- software/application
- Weaknesses
- CWE-79
Affected products
- invisioncommunity / invision_power_board
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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