CVE-2021-43558

Name: CVE-2021-43558
Creator: NVD / NIST
Published: 2021-11-22T16:15:08.237+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.1/10EPSS 0.84%

Last modified Jun 17, 2026

CVE-2021-43558 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. A flaw was found in Moodle in versions 3.11 to 3.11.3, 3.10 to 3.10.7, 3.9 to 3.9.10 and earlier unsupported versions. A URL parameter in the filetype site administrator tool required extra sanitizing to prevent a reflected XSS risk.. EPSS estimates a 0.84% chance of exploitation in the next 30 days.

Description

A flaw was found in Moodle in versions 3.11 to 3.11.3, 3.10 to 3.10.7, 3.9 to 3.9.10 and earlier unsupported versions. A URL parameter in the filetype site administrator tool required extra sanitizing to prevent a reflected XSS risk.

Metrics

CVSS 3.1

6.1/10

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

EPSS Probability

0.84%

53.3th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Moodle	Moodle	<= 3.8.8
Moodle	Moodle	>= 3.9.0, < 3.9.11
Moodle	Moodle	>= 3.10.0, < 3.10.8
Moodle	Moodle	>= 3.11.0, < 3.11.4
Fedoraproject	Extra Packages For Enterprise Linux	7.0
Fedoraproject	Fedora	35

References

https://bugzilla.redhat.com/show_bug.cgi?id=2021515Issue Tracking, Third Party Advisory
https://moodle.org/mod/forum/discuss.php?d=429097Patch, Vendor Advisory
https://bugzilla.redhat.com/show_bug.cgi?id=2021515Issue Tracking, Third Party Advisory
https://moodle.org/mod/forum/discuss.php?d=429097Patch, Vendor Advisory

Timeline

Published: Nov 22, 2021
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2021-43558?

How severe is CVE-2021-43558?

CVE-2021-43558 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 0.84% probability of exploitation in the next 30 days.

How do I fix CVE-2021-43558?

Check the vendor references and advisories linked above for patched versions and mitigation guidance. You can also run a Strix scan to test if your systems are affected.

Are you affected by CVE-2021-43558?

Run a free Strix scan to check your systems for this vulnerability.

Scan your code now

Source: NVD / NIST