Vulnerability identifier: #VU54334

Vulnerability risk: Low

CVSSv3.1: 6.7 [CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H/E:F/RL:O/RC:C]

CVE-ID: CVE-2021-21809

CWE-ID: CWE-78

Exploitation vector: Network

Exploit availability: Yes

Vulnerable software:
Moodle
Web applications / Other software

Vendor: moodle.org

Description

The vulnerability allows a remote user to execute arbitrary shell commands on the target system.

The vulnerability exists due to improper input validation in the default legacy spellchecker plugin. A remote administrator can pass specially crafted data to the application and execute arbitrary OS commands 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

Moodle: 3.10.0

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External links
http://www.talosintelligence.com/vulnerability_reports/TALOS-2021-1277

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Q & A

Can this vulnerability be exploited remotely?

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

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability. However, a fully functional exploit for this vulnerability is available.