Cross-site request forgery (CSRF) vulnerability in goform/usermanage in Grandstream GXV3501 GXV3504 GXV3601 GXV3601HD/LL GXV3611HD/LL GXV3615W/P GXV3651FHD GXV3662HD GXV3615WP_HD GXV3500 and possibly other camera models allows remote attackers to hijack the authentication of unspecified victims for requests that add users.