CVE-2021-20185

mediumpriority · track · 21EPSS 0.014 · 72 %ileEURUUS

grimoire priorityP3 · Track

Exploitable?

—

no known exploitation

Likely / severe?

1.39% (72nd) EPSS

CVSS 5 · medium

Is it mine?

18 products

Check your exposure

Who says so?

5 sources

cnnvd · enisa_euvd · fstec_bdu · osv

EPSS · scored 2026-10-27

It was found in Moodle before version 3.10.1, 3.9.4, 3.8.7 and 3.5.16 that messaging did not impose a character limit when sending messages, which could result in client-side (browser) denial of service for users receiving very large messages.

cvss

Technical severity, 0–10. One row per scoring source.

5.3

010

base score 0–10 · higher = more severe · hover a vector to decode

v2.05mediumAV:N/AC:L/Au:N/C:N/I:N/A:Pprimary · NVD / NIST USexploitability 10 · impact 2.9

v3.15.3mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Lprimary · NVD / NIST USexploitability 3.9 · impact 1.4

v3.15.3mediumAV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Lsecondary · FSTEC (BDU) RU

v3.15.3mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:Lsecondary · OSV

v3.14.9mediumCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:Usecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-770USprimaryCWE-400USCWE-400USCWE-400USCWE-770US

affected products (18)

Products and version ranges known to be affected.

n/a Moodle≤ moodle 3.10.1, moodle 3.9.4, moodle 3.8.7, moodle 3.5.16enisa_euvdEU
Мартин Догиамас Moodle3.10.0 → 3.10.1fstec_bduRU
Мартин Догиамас Moodle3.5.0 → 3.5.16fstec_bduRU
Мартин Догиамас Moodle3.8.0 → 3.8.7fstec_bduRU
Мартин Догиамас Moodle3.9.0 → 3.9.4fstec_bduRU
ООО «Ред Софт» РЕД ОС≤ 7.2 Муромfstec_bduRU
moodle moodle= 3.10.0nvdUScpe:2.3:a:moodle:moodle:*:*:*:*:*:*:*:*
moodle moodle3.5.0 → 3.5.16nvdUScpe:2.3:a:moodle:moodle:*:*:*:*:*:*:*:*
moodle moodle3.8.0 → 3.8.7nvdUScpe:2.3:a:moodle:moodle:*:*:*:*:*:*:*:*
moodle moodle3.9.0 → 3.9.4nvdUScpe:2.3:a:moodle:moodle:*:*:*:*:*:*:*:*
Bitnami moodle3.10.0 → 3.10.1osvUSpkg:bitnami/moodle
Bitnami moodle3.5.0 → 3.5.16osvUSpkg:bitnami/moodle
Bitnami moodle3.8.0 → 3.8.7osvUSpkg:bitnami/moodle
Bitnami moodle3.9.0 → 3.9.4osvUSpkg:bitnami/moodle
Packagist moodle/moodle3.10 → 3.10.1osvUSpkg:composer/moodle/moodle
Packagist moodle/moodle3.5 → 3.5.16osvUSpkg:composer/moodle/moodle
Packagist moodle/moodle3.8 → 3.8.7osvUSpkg:composer/moodle/moodle
Packagist moodle/moodle3.9 → 3.9.4osvUSpkg:composer/moodle/moodle

advisories (2)

Vendor and ecosystem advisories describing this.

GHSA-c3j6-33r4-89q3Moodle Client side denial of service via personal message2022-05-24ghsa · osvUS
It was found in Moodle before version 3.10.1, 3.9.4, 3.8.7 and 3.5.16 that messaging did not impose a character limit when sending messages, which could result in client-side (browser) denial of service for users receiving very large messages.
BIT-moodle-2021-201852024-03-06vendor · osvUS
It was found in Moodle before version 3.10.1, 3.9.4, 3.8.7 and 3.5.16 that messaging did not impose a character limit when sending messages, which could result in client-side (browser) denial of service for users receiving very large messages.

also known as (6)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd fstec_bdu osv nvd NVD CVE.org MITRE

published 2021-01-28modified 2026-06-17

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+3263 more

references (6)

External citations — patches, advisories, analysis.

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