CVE-2021-23393
MEDIUMFlask-Unchained < 0.9.0 - Open Redirect via Backslash Bypass in _validate_redirect_url
Title source: llmDescription
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.
References (2)
Core 2
Core References
Patch, Third Party Advisory x_refsource_misc
https://snyk.io/vuln/SNYK-PYTHON-FLASKUNCHAINED-1293189
Patch, Third Party Advisory x_refsource_misc
https://github.com/briancappello/flask-unchained/commit/71e36b28166f9ffbe0a991f51127f0984f7e6a40
Scores
CVSS v3
5.4
EPSS
0.0072
EPSS Percentile
48.9%
Attack Vector
NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
Details
CWE
CWE-601
Status
published
Products (2)
flask_unchained_project/flask_unchained
< 0.9.0
pypi/Flask-Unchained
0 - 0.9.0PyPI
Published
Jun 11, 2021
Tracked Since
Feb 18, 2026