{"cve":"CVE-2021-23385","nvd":{"published":"2022-08-02T14:15:10.017","modified":"2026-06-17T03:38:39.950","status":"Modified","description":"This affects all versions of package Flask-Security. When using the get_post_logout_redirect and get_post_login_redirect functions, 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. **Note:** Flask-Security is not maintained anymore.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","score":6.1},"cwes":["CWE-601"],"references":["https://github.com/mattupstate/flask-security","https://lists.debian.org/debian-lts-announce/2023/08/msg00034.html","https://security.snyk.io/vuln/SNYK-PYTHON-FLASKSECURITY-1293234","https://snyk.io/blog/url-confusion-vulnerabilities/","https://github.com/mattupstate/flask-security"],"products":["flask-security_project:flask-security"],"source":"nvd","synced_at":"2026-10-19T21:34:18.502168378+00:00"},"epss":{"cve":"CVE-2021-23385","score":0.01247,"percentile":0.69342,"date":"2026-11-01"},"kev":null,"osv":[{"id":"GHSA-cg8c-gc2j-2wf7","url":"https://osv.dev/vulnerability/GHSA-cg8c-gc2j-2wf7","summary":"Flask-Security vulnerable to Open Redirect","modified":"2026-07-07T11:56:49.533724357Z","packages":[{"ecosystem":"PyPI","name":"flask-security","purl":"pkg:pypi/flask-security","ranges":["<=3.0.0"],"fixed":[]}]},{"id":"PYSEC-2026-809","url":"https://osv.dev/vulnerability/PYSEC-2026-809","summary":"Flask-Security vulnerable to Open Redirect","modified":"2026-07-07T11:45:45.877626931Z","packages":[{"ecosystem":"PyPI","name":"flask-security","purl":"pkg:pypi/flask-security","ranges":["<5.5.1"],"fixed":["5.5.1"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}