ownCloud is prone to a URI open-redirection vulnerability, multiple cross-site scripting vulnerabilities and multiple HTML-injection vulnerabilities because it fails to properly sanitize user-supplied input. An attacker could leverage the cross-site scripting issues to execute arbitrary script code in the browser of an unsuspecting user in the context of the affected site. This may let the attacker steal cookie-based authentication credentials and launch other attacks. Attacker-supplied HTML and script code would run in the context of the affected browser, potentially allowing the attacker to steal cookie-based authentication credentials or control how the site is rendered to the user. Other attacks are also possible. Successful exploits may redirect a user to a potentially malicious site; this may aid in phishing attacks.