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URL Redirection to Untrusted Site ('Open Redirect')

CVE-2021-23393

Medium
5.4/10

Summary

This affects the package Flask-Unchained before 0.9.0. When using the the _validate_redirect_url function, it is possible to bypass URL validation and redirect a user to an arbitrary URL by providing multiple back slashes such as \\\evil.com/path. This vulnerability is only exploitable if an alternative WSGI server other than Werkzeug is used, or the default behaviour of Werkzeug is modified using 'autocorrect_location_header=False.

  • LOW
  • NETWORK
  • LOW
  • UNCHANGED
  • REQUIRED
  • NONE
  • LOW
  • NONE

CWE-601 - Open Redirect

An open redirect attack employs a URL parameter, HTML refresh tags, or a DOM based location change to exploit the trust of a vulnerable domain to direct the users to a malicious website. The attack could lead to higher severity vulnerabilities such as unauthorized access control, account takeover, XSS, and more.

References

Advisory Timeline

  • Published