An issue was discovered in Craft CMS before 3.6.7. In some circumstances, a potential Remote Code Execution vulnerability existed on sites that did not restrict administrative changes (if an attacker were somehow able to hijack an administrator's session).

References

• https://nvd.nist.gov/vuln/detail/CVE-2021-27903
• craftcms/cms@c17728f
• https://github.com/craftcms/cms/blob/develop/CHANGELOG.md#367---2021-02-23
• https://github.com/craftcms/cms/blob/develop/CHANGELOG.md#security