Cross-site scripting (XSS) vulnerability in send_email.php in AN Guestbook (ANG) 0.4 allows remote attackers to inject arbitrary web script or HTML via the postid parameter.
https://exchange.xforce.ibmcloud.com/vulnerabilities/42489
http://www.z0rlu.ownspace.org/index.php?/archives/86-ANG-AN-Guestbook-version-0.4-xss.html