CVE-2021-23385

Publication date 2 August 2022

Last updated 25 August 2025

Ubuntu priority

Cvss 3 Severity Score

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.

Status

Show unmaintained releases

Package	Ubuntu Release	Status
flask-security	24.04 LTS noble	Not affected
	23.10 mantic	Not affected
	23.04 lunar	Ignored end of life, was needs-triage
	22.10 kinetic	Ignored end of life, was needs-triage
	22.04 LTS jammy	Fixed 4.0.0-1ubuntu0.1
	21.10 impish	Ignored end of life
	21.04 hirsute	Ignored end of life
	20.10 groovy	Ignored end of life
	20.04 LTS focal	Fixed 1.7.5-2ubuntu0.20.04.1
	18.04 LTS bionic	Fixed 1.7.5-2ubuntu0.18.04.1~esm1
	16.04 LTS xenial	Not in release
	14.04 LTS trusty	Not in release

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Severity score breakdown

Parameter	Value
Base score	6.1 · Medium
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	Required
Scope	Changed
Confidentiality	Low
Integrity impact	Low
Availability impact	None
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

References

Related Ubuntu Security Notices (USN)

USN-6792-1
Flask-Security vulnerability
28 May 2024