Affected: getgrav grav-plugin-guestbook

Grav Guestbook plugin before 0.5.2 contains a stored cross-site scripting vulnerability because its AJAX Load more and Admin Load all handlers insert stored author and message fields into the DOM as unescaped HTML via jQuery. Unauthenticated visitors can submit markup that executes in other visitors' browsers and, in versions 0.5.0 and 0.5.1, in administrator moderation sessions.