5.4

CVE-2021-36399: moodle Cross-site Scripting

CVSS: 5.4v3.1MediumModified
AliasesUBUNTU-CVE-2021-36399
Published 06-03-2023Last modified 07-03-2025
Open JSON

Vulnerability summary

CVE-2021-36399 is a medium (CVSS 5.4) Cross-site Scripting vulnerability in moodle. EPSS estimates a 0.52% chance of exploitation in the next 30 days, higher than 42.9% of scored vulnerabilities.

Overall risk
22/100
0100
Low · default modelHow is this calculated?
CVSS score
5.4/10
010
Medium · v3.1 (CVE.org)
EPSS score
0.52%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded

Timeline

  1. 06-03-2023
    PublishedVulnerability first disclosed.
  2. 07-03-2025
    Last modifiedVulnerability information updated.

Description

In Moodle, ID numbers displayed in the quiz override screens required additional sanitizing to prevent a stored XSS risk.

CVSS metrics

3 scores · 3 sources · 1 version

EPSS trend

Probability

0.52%

Chance of exploitation in the next 30 days

Percentile

43%

Versus all other CVEs

30-day change

0.00 pp

From 0.52% on 21-09-2026

21-09-202621-10-2026
EPSS score
0.52%

Known exploited

Compare KEV catalogs

Not in any of the 3 tracked catalogs.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Moodle1 product
Ubuntu1 product
  • moodleAll versions (No fix recorded)

2 vendors · 2 products

References

3 links