PYSEC-2026-809

    Dashboard / Vulnerabilities / PYSEC-2026-809

    PYSEC-2026-809

    Published: 7 Jul 2026Last Modified: 7 Jul 2026

    Summary: Flask-Security vulnerable to Open Redirect

    Details: 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.

    References: https://nvd.nist.gov/vuln/detail/CVE-2021-23385, https://github.com/mattupstate/flask-security, https://security.snyk.io/vuln/SNYK-PYTHON-FLASKSECURITY-1293234, https://snyk.io/blog/url-confusion-vulnerabilities, https://pypi.org/project/flask-security, https://github.com/advisories/GHSA-cg8c-gc2j-2wf7

    Affected packages

    Package

    Name: flask-security

    Purl: pkg:pypi/flask-security

    Affected ranges

    Type: ECOSYSTEM

    Events:

    Introduced- 0
    Fixed -5.5.1

    Affected versions

    1.2.0
    1.2.1
    1.2.2
    1.2.3

    Common Vulnerability Scoring System

    Attack Vector
    Network
    Adjacent
    Local
    Physical
    Privileges Required
    None
    Low
    High
    User Interaction
    None
    Required
    Scope
    Unchanged
    Changed
    Confidentiality
    None
    Low
    High
    Integrity
    None
    Low
    High
    Availability
    None
    Low
    High
    PYSEC-2026-809 | CVE-DB