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Vulnerability details: VCID-nntc-dsz1-e3fp
Vulnerability ID VCID-nntc-dsz1-e3fp
Aliases CVE-2021-20186
GHSA-h8m4-h385-qhqv
Summary Cross-site Scripting It was found in Moodle that if the TeX notation filter was enabled, additional sanitizing of TeX content was required to prevent the risk of stored XSS.
Status Published
Exploitability 0.5
Weighted Severity 6.2
Risk 3.1
Affected and Fixed Packages Package Details
Weaknesses (3)
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
System Score Found at
epss 0.0053 https://api.first.org/data/v1/epss?cve=CVE-2021-20186
cvssv3.1 5.4 https://github.com/moodle/moodle
generic_textual MODERATE https://github.com/moodle/moodle
cvssv3.1 5.4 https://moodle.org/mod/forum/discuss.php?d=417170
generic_textual MODERATE https://moodle.org/mod/forum/discuss.php?d=417170
cvssv3.1 5.4 https://nvd.nist.gov/vuln/detail/CVE-2021-20186
generic_textual MODERATE https://nvd.nist.gov/vuln/detail/CVE-2021-20186
Reference id Reference type URL
https://api.first.org/data/v1/epss?cve=CVE-2021-20186
https://github.com/moodle/moodle
https://moodle.org/mod/forum/discuss.php?d=417170
CVE-2021-20186 https://nvd.nist.gov/vuln/detail/CVE-2021-20186
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N Found at https://github.com/moodle/moodle
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N Found at https://moodle.org/mod/forum/discuss.php?d=417170
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2021-20186
Attack Vector (AV) Attack Complexity (AC) Privileges Required (PR) User Interaction (UI) Scope (S) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

network

adjacent_network

local

physical

low

high

none

low

high

none

required

unchanged

changed

high

low

none

high

low

none

high

low

none
Exploit Prediction Scoring System (EPSS)
Percentile 0.67569
EPSS Score 0.0053
Published At June 4, 2026, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2026-06-04T16:20:45.870211+00:00 GitLab Importer Import https://gitlab.com/gitlab-org/advisories-community/-/blob/main/packagist/moodle/moodle/CVE-2021-20186.yml 38.6.0