What is CVE-2023-23921?

CVE-2023-23921 is a medium-severity vulnerability in Moodle, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2023-02-17.

How severe is CVE-2023-23921?

Medium severity. CVSS v3 base score is 6.1 out of 10.

Is CVE-2023-23921 known to be exploited?

1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

XSS in Moodle

CVE-2023-23921

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.

Vulnerability class: XSS (Cross-Site Scripting)

EPSS: 0.008 (53.3th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 6.1 (Medium). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.

Affected products

Moodle — versions 4.1.0

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

Public proof-of-concept exploits

jev770/badmoodle-scan

References

patrick@puiterwijk.org (Patch)
patrick@puiterwijk.org (Third Party Advisory, Issue Tracking)
patrick@puiterwijk.org (Patch, Vendor Advisory)

Frequently asked questions

What is CVE-2023-23921?: CVE-2023-23921 is a medium-severity vulnerability in Moodle, classified under Cross-site Scripting. CVSS score: 6.1/10. Published 2023-02-17.
How severe is CVE-2023-23921?: Medium severity. CVSS v3 base score is 6.1 out of 10.
Is CVE-2023-23921 known to be exploited?: 1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.