CVE & CISA-KEV Catalog

CVE-2021-23385

MEDIUM
5.4
CVSS v3
NVD

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.

CWE-601Open Redirect

How to fix

Remediation Available
flask-securityDebian
Fixed in:4.0.0-1+deb11u1CVE-2021-23385
Fixed in:5.0.2-1CVE-2021-23385
Fixed in:5.0.2-1CVE-2021-23385
Fixed in:5.0.2-1CVE-2021-23385
flask-securityUbuntu
Fixed in:1.7.5-2ubuntu0.18.04.1~esm1USN-6792-1
Fixed in:1.7.5-2ubuntu0.20.04.1USN-6792-1
Fixed in:4.0.0-1ubuntu0.1USN-6792-1
python3-flask-securityUbuntu
Fixed in:1.7.5-2ubuntu0.18.04.1~esm1USN-6792-1
Fixed in:1.7.5-2ubuntu0.20.04.1USN-6792-1
Fixed in:4.0.0-1ubuntu0.1USN-6792-1

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityLow
Privileges RequiredNone
User InteractionRequired
ScopeUnchanged

Impact

ConfidentialityLow
IntegrityLow
AvailabilityNone

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

Exploit Intelligence

0.90%probability of exploitation in 30 days
55thpercentile

Moderate risk: more likely to be exploited than 55% of all known CVEs.

References

Third-Party Advisory2
Other references1

Related Vulnerabilities

Other CWE-601 (Open Redirect) vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2025-4123High7.698%-Fix
CVE-2018-11784Medium4.394%-Fix
CVE-2021-22881Medium6.187%-Fix
CVE-2022-45402Medium6.182%-Fix
CVE-2017-1000117High8.878%-Fix
CVE-2019-10098Medium6.174%-Fix
Embed a live status badge for CVE-2021-23385
CVE-2021-23385 severity badge

Markdown

[![CVE-2021-23385](https://tridentstack.com/cve/badge/CVE-2021-23385.svg)](https://tridentstack.com/cve/CVE-2021-23385)

HTML

<a href="https://tridentstack.com/cve/CVE-2021-23385"><img src="https://tridentstack.com/cve/badge/CVE-2021-23385.svg" alt="CVE-2021-23385"></a>

Find and fix vulnerabilities across your fleet

TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.

Start free

This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2024-11-21.