Moodle command execution vulnerability exists in the default legacy spellchecker plugin

CRITICAL 9.1CVE-2021-21809 · BIT-moodle-2021-21809 · GHSA-c7jj-vfmr-j9mj · Published 23/06/2021 · updated 17/06/2026

Package	Affected versions	Patched versions
moodle/moodle Packagist	`= 3.10.0= 3.11.2= 3.8.0`	No fix yet
moodle moodle	`= 3.10.0`	No fix yet

Description

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.

NVD description

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.

References

nvd.nist.gov/vuln/detail/CVE-2021-21809 · ADVISORY
moodle/moodle · PACKAGE
talosintelligence.com/vulnerability_reports/TALOS-2021-1277 · WEB
packetstormsecurity.com/files/164481/Moodle-SpellChecker-Path-Authenticated-Remote-Command-Execution.html · WEB

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