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).
The SEOmatic component before 3.3.0 for Craft CMS allows Server-Side Template Injection that leads to RCE via malformed data to the metacontainers controller.
In Craft CMS through 3.1.7, the elevated session password prompt was not being rate limited like normal login forms, leading to the possibility of a brute force attempt on them.
Craft CMS through 3.0.34 allows remote authenticated administrators to read sensitive information via server-side template injection, as demonstrated by a {% string for craft.app.config.DB.user and craft.app.config.DB.password in the URI Format of the Site Settings, which causes a cleartext username and password to be displayed in a URI field.
Craft CMS before 2.6.2976 allows XSS attacks because an array returned by HttpRequestService::getSegments() and getActionSegments() need not be zero-based. NOTE: this vulnerability exists because of an incomplete fix for CVE-2017-8052.