CVE-2021-21809

highpriority · attend · 54EPSS 0.242 · 98 %ileexploit · weaponizedEUUS

grimoire priorityP1 · Urgent

Exploitable?

Public exploit

2 exploits · weaponized

Likely / severe?

24.2% (98th) EPSS

CVSS 9 · high

Is it mine?

4 products

Check your exposure

Who says so?

4 sources

cnnvd · enisa_euvd · osv · nvd

EPSS · scored 2026-10-24

A command execution vulnerability exists in the default legacy spellchecker plugin in Moodle 3.10. A specially crafted series of HTTP requests can lead to command execution. An attacker must have administrator privileges to exploit this vulnerabilities.

cvss

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

9.1

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · high–critical · 8.2–9.1

v2.09highAV:N/AC:L/Au:S/C:C/I:C/A:Cprimary · NVD / NIST USexploitability 8 · impact 10

v3.19.1criticalCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 2.3 · impact 6

v3.08.2highCVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:L/A:Lsecondary · ENISA EU

v3.08.2highCVSS:3.0/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:L/A:Lsecondary · talos-cna@cisco.com USexploitability 2.3 · impact 5.3

v3.19.1criticalCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:Hsecondary · OSV

v3.18.9highCVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H/E:Fsecondary · CVSS-BT (t0sche)

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-78USprimaryCWE-732US

exploits (2)

Public proof-of-concept and weaponised exploit code.

exploit/multi/http/moodle_spelling_path_rceMoodle SpellChecker Path Authenticated Remote Command Executionweaponized · metasploit
anldori/CVE-2021-21809CVE-2021-21809 POCPoC · poc_in_github

affected products (4)

Products and version ranges known to be affected.

n/a Moodle≤ Moodle 3.10enisa_euvdEU
moodle moodle= 3.10.0nvdUScpe:2.3:a:moodle:moodle:*:*:*:*:*:*:*:*
Bitnami moodle3.10.0 → 3.10.1osvUSpkg:bitnami/moodle
Packagist moodle/moodleall versionsosvUSpkg:composer/moodle/moodle

advisories (2)

Vendor and ecosystem advisories describing this.

GHSA-c7jj-vfmr-j9mjMoodle command execution vulnerability exists in the default legacy spellchecker plugin2022-05-24ghsa · osvUS
A command execution vulnerability exists in the default legacy spellchecker plugin in a few Moodle multiple specific versions. A specially crafted series of HTTP requests can lead to command execution. An attacker must have administrator privileges to exploit this vulnerabilities.
BIT-moodle-2021-218092024-03-06vendor · osvUS
A command execution vulnerability exists in the default legacy spellchecker plugin in Moodle 3.10. A specially crafted series of HTTP requests can lead to command execution. An attacker must have administrator privileges to exploit this vulnerabilities.

also known as (5)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd osv nvd NVD CVE.org MITRE

published 2021-06-23modified 2026-06-17

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references (9)

External citations — patches, advisories, analysis.

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