#VU67591 Open redirect in Python - CVE-2021-28861

Vulnerability identifier: #VU67591

Vulnerability risk: Low

CVSSv4.0: 0.5 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:L/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Clear]

CVE-ID: CVE-2021-28861

CWE-ID: CWE-601

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Python
Universal components / Libraries / Scripting languages

Vendor: Python.org

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 lib/http/server.py due to missing protection against multiple (/) at the beginning of URI path. 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

Python: 3.0 - 3.0.1, 3.1 - 3.10.5, 3.2 - 3.2.2150, 3.3 - 3.3.7, 3.4 - 3.4.10, 3.5 - 3.5.10, 3.6 - 3.6.15, 3.7 - 3.7.13, 3.8 - 3.8.13, 3.9.0b4 - 3.9.13

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External links
https://github.com/python/cpython/pull/93879
https://bugs.python.org/issue43223
https://github.com/python/cpython/pull/24848
https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/OKYE2DOI2X7WZXAWTQJZAXYIWM37HDCY/

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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.