CVE-2021-36400: moodle Incorrect Default Permissions
CVSS: 5.3v3.1MediumModified
AliasesUBUNTU-CVE-2021-36400
Published 06-03-2023Last modified 07-03-2025
Vulnerability summary
CVE-2021-36400 is a medium (CVSS 5.3) Incorrect Default Permissions vulnerability in moodle. EPSS estimates a 0.51% chance of exploitation in the next 30 days, higher than 42.2% of scored vulnerabilities.
CVSS score
5.3/10
010
Medium · v3.1 (CVE.org)EPSS score
0.51%
0%100%
Low · 0.00 pp in 30 daysKEVNot listedIn no KEV catalog
RansomwareNone recordedNo known use recorded
Public exploits0No public exploits recorded
Timeline
- 06-03-2023PublishedVulnerability first disclosed.
- 07-03-2025Last modifiedVulnerability information updated.
Description
In Moodle, insufficient capability checks made it possible to remove other users' calendar URL subscriptions.
CVSS metrics
3 scores · 3 sources · 1 versionMedium 5.3Preferred score · CVE.org (CNA)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:NSourcesAll 3 agree
- OSV · UbuntuEcosystem advisory · calculated5.3MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- NVDNIST5.3MediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
EPSS trend
Probability
0.51%
Chance of exploitation in the next 30 days
Percentile
42%
Versus all other CVEs
30-day change
0.00 pp
From 0.51% on 21-09-2026
21-09-202621-10-2026
EPSS score0.51%
Known exploited
Compare KEV catalogsNot in any of the 3 tracked catalogs.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root cause- CWE-276Incorrect Default PermissionsDuring installation, installed file permissions are set to allow anyone to modify those files.
- CWE-639Authorization Bypass Through User-Controlled KeyThe system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.
Affected systems
Moodle1 product
- moodle< 3.9.8 | ≥ 3.10.0, < 3.10.5 | ≥ 3.11.0, < 3.11.1
Ubuntu1 product
- moodleAll versions (No fix recorded)
2 vendors · 2 products