Open redirect in Flask-Unchained

1) Open redirect

EUVDB-ID: #VU59529

Risk: Medium

CVSSv3.1: 4.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-23393

CWE-ID: CWE-601 - URL Redirection to Untrusted Site ('Open Redirect')

Exploit availability: No

Description

The vulnerability allows a remote attacker to redirect victims to arbitrary URL.

The vulnerability exists due to improper sanitization of user-supplied data in the "the _validate_redirect_url" function. A remote attacker can create a link that leads to a trusted website, however, when clicked, redirects the victim to arbitrary domain.

Successful exploitation of this vulnerability may allow a remote attacker to perform a phishing attack and steal potentially sensitive information.

Mitigation

Install updates from vendor's website.

Vulnerable software versions

Flask-Unchained: 0.1.0 - 0.8.1

CPE2.3

• cpe:2.3:a:brian_cappello:flask-unchained:0.8.1:*:*:*:*:*:*:*
• cpe:2.3:a:brian_cappello:flask-unchained:0.8.0:*:*:*:*:*:*:*
• cpe:2.3:a:brian_cappello:flask-unchained:0.7.9:*:*:*:*:*:*:*

External links

http://snyk.io/vuln/SNYK-PYTHON-FLASKUNCHAINED-1293189
http://github.com/briancappello/flask-unchained/commit/71e36b28166f9ffbe0a991f51127f0984f7e6a40

Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.