source: http://www.securityfocus.com/bid/17484/info

Plone is susceptible to a remote access-control bypass vulnerability. This issue is due to the application's failure to properly enforce privileges to various MembershipTool methods.

This issue allows remote, anonymous attackers to modify and delete portrait images of members. This may help attackers exploit latent vulnerabilities in image-rendering software. Other attacks may also be possible.

curl -F portrait=<path_to_file> --form-string member_id=[username] http://www.example.com/portal_membership/changeMemberPortrait