Vulnerability identifier: #VU49970

Vulnerability risk: Low

CVSSv3.1: 3.8 [CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L/E:U/RL:O/RC:C]

CVE-ID: CVE-2021-20185

CWE-ID: CWE-399

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Moodle
Web applications / Other software

Vendor: moodle.org

Description

The vulnerability allows a remote attacker to perform a denial of service (DoS) attack.

The vulnerability exists due to the application does not impose limits on the number of characters sent via messages. A remote user can send an overly long message and perform a client-side (browser) denial of service attack.

Mitigation
Install updates from vendor's website.

Vulnerable software versions

Moodle: 3.5.0 - 3.5.15, 3.7.0 - 3.7.9, 3.8.0 - 3.8.6, 3.9.0 - 3.9.3, 3.10.0, 3.3 - 3.3.9, 3.6.0 - 3.6.10, 3.1.0 - 3.1.18, 3.4.0 - 3.4.9, 3.2.0 - 3.2.9, 3.0 - 3.0.10

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External links
http://moodle.org/mod/forum/discuss.php?d=417168

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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.