CVE-2021-20186 json
Moodle Cross-site Scripting
published 2021-01-28 5 y ago modified 2026-09-08 2 mo ago also BIT-moodle-2021-20186 , EUVD-2022-4109 , GHSA-h8m4-h385-qhqv
- cvss
- 5.4
- version 3.1, NVD
- cisa kev
- Not listed
- not in CISA's catalog
- epss
- 0.8%
- EPSS 0.8% chance of exploitation in 30 days, percentile 55%
- public exploits
- 0
- none known
Summary
It was found in Moodle before version 3.10.1, 3.9.4, 3.8.7 and 3.5.16 that if the TeX notation filter was enabled, additional sanitizing of TeX content was required to prevent the risk of stored XSS.
Patch / fix
- packagist moodle/moodle 3.5.16, 3.8.7, 3.9.4, 3.10.1
- bitnami moodle 3.5.16, 3.8.7, 3.9.4, 3.10.1
- moodle moodle 3.5.16, 3.8.7, 3.9.4, 3.10.1
Exploit prediction
0.76% chance of exploitation in the next 30 days, higher than 55% of all scored CVEs (FIRST EPSS, 2026-11-08).
CVSS scores
| assigned by | version | score | vector |
|---|---|---|---|
| GitHub | 3.1 | 5.4 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N |
| NVD | 3.1 | 5.4 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N |
| NVD | 2.0 | 2.1 | AV:N/AC:H/Au:S/C:P/I:N/A:N |
| OSV | 3.1 | 5.4 | CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N |
Affected packages
| ecosystem | package | affected | fixed in |
|---|---|---|---|
| packagist | moodle/moodle | >=3.10, <3.10.1 >=3.9, <3.9.4 >=3.8, <3.8.7 >=3.5, <3.5.16 |
3.10.1 3.9.4 3.8.7 3.5.16 |
| bitnami | moodle | <3.5.16 >=3.8.0, <3.8.7 >=3.9.0, <3.9.4 >=3.10.0, <3.10.1 |
3.5.16 3.8.7 3.9.4 3.10.1 |
Affected products
- n/a moodle
Classification
- Weakness
-
- CWE-79 Improper Neutralization of Input During Web Page Generation
References
-
moodle.org
/mod/forum/discuss.php?d=417170
web, patch, vendor-advisory, advisory
-
nvd.nist.gov
/vuln/detail/CVE-2021-20186
advisory, web
-
github.com
/moodle/moodle
package
Sources
- CVE List CVE-2021-20186
- GitHub Advisory GHSA-h8m4-h385-qhqv
- NVD CVE-2021-20186
- OSV BIT-moodle-2021-20186
Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.