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Vulnerability details: VCID-6kw8-t3ku-wbc8
Vulnerability ID VCID-6kw8-t3ku-wbc8
Aliases CVE-2021-20186
GHSA-h8m4-h385-qhqv
Summary Moodle Cross-site Scripting 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.
Status Published
Exploitability 0.5
Weighted Severity 6.2
Risk 3.1
Affected and Fixed Packages Package Details
Weaknesses (3)
CWE-79 Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
System Score Found at
epss 0.00585 https://api.first.org/data/v1/epss?cve=CVE-2021-20186
epss 0.00585 https://api.first.org/data/v1/epss?cve=CVE-2021-20186
cvssv3.1_qr MODERATE https://github.com/advisories/GHSA-h8m4-h385-qhqv
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
cvssv2 2.1 https://nvd.nist.gov/vuln/detail/CVE-2021-20186
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
https://nvd.nist.gov/vuln/detail/CVE-2021-20186
cpe:2.3:a:moodle:moodle:*:*:*:*:*:*:*:* https://nvd.nist.gov/vuln/search/results?adv_search=true&isCpeNameSearch=true&query=cpe:2.3:a:moodle:moodle:*:*:*:*:*:*:*:*
GHSA-h8m4-h385-qhqv https://github.com/advisories/GHSA-h8m4-h385-qhqv
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: AV:N/AC:H/Au:S/C:P/I:N/A:N Found at https://nvd.nist.gov/vuln/detail/CVE-2021-20186
Exploitability (E) Access Vector (AV) Access Complexity (AC) Authentication (Au) Confidentiality Impact (C) Integrity Impact (I) Availability Impact (A)

high

functional

unproven

proof_of_concept

not_defined

local

adjacent_network

network

high

medium

low

multiple

single

none

none

partial

complete

none

partial

complete

none

partial

complete
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 0.68028
EPSS Score 0.00585
Published At June 30, 2025, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2025-07-01T12:28:55.113741+00:00 GithubOSV Importer Import https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2022/05/GHSA-h8m4-h385-qhqv/GHSA-h8m4-h385-qhqv.json 36.1.3