Jax Guestbook 3.5.0 allows remote attackers to bypass authentication and modify administrator settings via a direct request to admin/guestbook.admin.php.

Jax Guestbook 3.1 and 3.31 stores sensitive information under the web root with insufficient access control, which allows remote attackers to obtain IP addresses of users via a direct request to (1) guestbook, (2) guestbook_ips2block, (3) ips2block, and (4) formmailer/logfile.csv.

Multiple cross-site scripting (XSS) vulnerabilities in jax_guestbook.php in Jax Guestbook 3.1 and 3.31 allow remote attackers to inject arbitrary web script or HTML via the (1) gmt_ofs and (2) language parameters. NOTE: the page parameter is already covered by CVE-2006-1913. NOTE: it was later reported that 3.50 is also affected.

Cross-site scripting (XSS) vulnerability in jax_guestbook.php in Jax Guestbook 3.1, 3.31, and 3.50 allows remote attackers to inject arbitrary web script or HTML via the page parameter.