CVE-2023-23921

Name: CVE-2023-23921
Creator: NVD / NIST
Published: 2023-02-17T20:15:11.807+00:00
License: https://creativecommons.org/publicdomain/zero/1.0/

MEDIUMCVSS 6.1/10EPSS 0.81%

Last modified Jun 17, 2026

CVE-2023-23921 is a medium-severity vulnerability rated 6.1/10 on the CVSS scale. The vulnerability was found Moodle which exists due to insufficient sanitization of user-supplied data in some returnurl parameters. A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in user's browser in context of vulnerable website. EPSS estimates a 0.81% chance of exploitation in the next 30 days.

Description

The vulnerability was found Moodle which exists due to insufficient sanitization of user-supplied data in some returnurl parameters. A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in user's browser in context of vulnerable website. This flaw allows a remote attacker to perform cross-site scripting (XSS) attacks.

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

0.81%

52.4th percentile

Probability of exploitation in the next 30 days. Learn more

Weakness Enumeration

Affected Software

Vendor	Product	Versions
Moodle	Moodle	>= 3.9.0, < 3.9.19
Moodle	Moodle	>= 3.11.0, < 3.11.12
Moodle	Moodle	>= 4.0.0, < 4.0.6
Moodle	Moodle	4.1.0

References

http://git.moodle.org/gw?p=moodle.git&a=search&h=HEAD&st=commit&s=MDL-76810Patch
https://bugzilla.redhat.com/show_bug.cgi?id=2162526Issue Tracking, Third Party Advisory
https://moodle.org/mod/forum/discuss.php?d=443272#p1782021Patch, Vendor Advisory
http://git.moodle.org/gw?p=moodle.git&a=search&h=HEAD&st=commit&s=MDL-76810Patch
https://bugzilla.redhat.com/show_bug.cgi?id=2162526Issue Tracking, Third Party Advisory
https://moodle.org/mod/forum/discuss.php?d=443272#p1782021Patch, Vendor Advisory

Timeline

Published: Feb 17, 2023
Last Modified: Jun 17, 2026
Status: Modified

Frequently Asked Questions

What is CVE-2023-23921?

How severe is CVE-2023-23921?

CVE-2023-23921 has a CVSS score of 6.1/10 (MEDIUM severity). The EPSS model estimates a 0.81% probability of exploitation in the next 30 days.

How do I fix CVE-2023-23921?

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-2023-23921?

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

Scan your code now

Source: NVD / NIST