Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Ghost is a Node.js CMS. An unused endpoint added during the development of 4.0.0-alpha.3 has left sites vulnerable to untrusted users gaining access to Ghost Admin. Attackers can gain access by getting logged in users to click a link containing malicious code. Users do not need to enter credentials and may not know they've visited a malicious site. Ghost(Pro) has already been patched. We can find no evidence that the issue was exploited on Ghost(Pro) prior to the patch being added. Self-hosters are impacted if running Ghost a version between 4.0.0-alpha.3 and 4.3.2. Immediate action should be taken to secure your site. As the endpoint is unused, the patch simply removes it. As a workaround blocking access to "/ghost/preview "can also mitigate the issue.
CWE-79 - Cross Site Scripting
Cross-Site Scripting, commonly referred to as XSS, is the most dominant class of vulnerabilities. It allows an attacker to inject malicious code into a pregnable web application and victimize its users. The exploitation of such a weakness can cause severe issues such as account takeover, and sensitive data exfiltration. Because of the prevalence of XSS vulnerabilities and their high rate of exploitation, it has remained in the OWASP top 10 vulnerabilities for years.