Vulnerability identifier: #VU56454

Vulnerability risk: Low

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

CVE-ID: CVE-2021-40347

CWE-ID: CWE-284

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Postorius
Web applications / Webmail solutions

Vendor: GNU

Description

The vulnerability allows a remote user to gain unauthorized access to otherwise restricted functionality.

The vulnerability exists due to improper access restrictions in views/list.py. A remote user logged in into any account can send a specially crafted HTTP POST request to unsubscribe any user from a mailing list, also revealing whether that address was subscribed in the first place.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Postorius: 1.0.0 - 1.3.4 rc1

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External links
http://gitlab.com/mailman/postorius/-/commit/3d880c56b58bc26b32eac0799407d74b64b7474b
http://gitlab.com/mailman/postorius/-/tags
http://bugs.debian.org/cgi-bin/bugreport.cgi?bug=993746
http://gitlab.com/mailman/postorius/-/issues/531
http://phabricator.wikimedia.org/T289798
http://www.debian.org/security/2021/dsa-4970

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote authenticated user via the Internet.

Is there known malware, which exploits this vulnerability?

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