Vulnerability identifier: #VU57639

Vulnerability risk: High

CVSSv3.1: 8.7 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-41163

CWE-ID: CWE-94

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Discourse
Web applications / Forum & blogging software

Vendor: Civilized Discourse Construction Kit, Inc.

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to improper input validation in the "subscribe_url" parameter. A remote attacker can send a specially crafted request and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Discourse: 2.7.0 - 2.8.0 beta6

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External links
http://github.com/discourse/discourse/security/advisories/GHSA-jcjx-pvpc-qgwq
http://github.com/discourse/discourse/commit/fa3c46cf079d28b086fe1025349bb00223a5d5e9

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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.