Comment 1 for bug 1435179

The kdesudo failure was caused by these entries in /etc/sudoers:

After this lines:

Defaults env_reset
Defaults mail_badpass
Defaults secure_path="/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/sbin:/bin"

I had added these lines:

# Allow proxy environment variables to pass through
Defaults env_keep="no_proxy NO_PROXY"
Defaults env_keep+="all_proxy ALL_PROXY"
Defaults env_keep+="http_proxy HTTP_PROXY"
Defaults env_keep+="https_proxy HTTPS_PROXY"
Defaults env_keep+="ftp_proxy FTP_PROXY"

After removing these lines kdesudo working again.