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Vulnerability details: VCID-mhm4-8kuk-t7b6
Vulnerability ID VCID-mhm4-8kuk-t7b6
Aliases CVE-2021-20185
GHSA-c3j6-33r4-89q3
Summary Uncontrolled Resource Consumption It was found in Moodle that messaging does not impose a character limit when sending messages, which could result in client-side (browser) denial of service for users receiving very large messages.
Status Published
Exploitability 0.5
Weighted Severity 6.2
Risk 3.1
Affected and Fixed Packages Package Details
Weaknesses (4)
CWE-1035 OWASP Top Ten 2017 Category A9 - Using Components with Known Vulnerabilities
CWE-770 Allocation of Resources Without Limits or Throttling
CWE-937 OWASP Top Ten 2013 Category A9 - Using Components with Known Vulnerabilities
CWE-400 Uncontrolled Resource Consumption
System Score Found at
epss 0.00382 https://api.first.org/data/v1/epss?cve=CVE-2021-20185
cvssv3.1 5.3 https://github.com/moodle/moodle
generic_textual MODERATE https://github.com/moodle/moodle
cvssv3.1 5.3 https://moodle.org/mod/forum/discuss.php?d=417168
generic_textual MODERATE https://moodle.org/mod/forum/discuss.php?d=417168
cvssv3.1 5.3 https://nvd.nist.gov/vuln/detail/CVE-2021-20185
generic_textual MODERATE https://nvd.nist.gov/vuln/detail/CVE-2021-20185
Reference id Reference type URL
https://api.first.org/data/v1/epss?cve=CVE-2021-20185
https://github.com/moodle/moodle
https://moodle.org/mod/forum/discuss.php?d=417168
CVE-2021-20185 https://nvd.nist.gov/vuln/detail/CVE-2021-20185
No exploits are available.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L 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:N/UI:N/S:U/C:N/I:N/A:L Found at https://moodle.org/mod/forum/discuss.php?d=417168
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:N/UI:N/S:U/C:N/I:N/A:L Found at https://nvd.nist.gov/vuln/detail/CVE-2021-20185
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 0.59891
EPSS Score 0.00382
Published At June 4, 2026, 12:55 p.m.
Date Actor Action Source VulnerableCode Version
2026-06-04T16:20:45.913438+00:00 GitLab Importer Import https://gitlab.com/gitlab-org/advisories-community/-/blob/main/packagist/moodle/moodle/CVE-2021-20185.yml 38.6.0