YesWiki before 4.7.0 contains a cross-site request forgery vulnerability in the despam action (tools/security/actions/despam.php) that lets unauthenticated attackers delete or restore pages through an administrator's session. Attackers can plant an auto-submitting raw HTML form on a wiki page, so an administrator who views it posts clean, suppr[], or rev[] parameters that delete PagePrincipale, configuration pages, or overwrite current content.