I just want to post this in case anyone has a similar problem. I am running Plesk 7.5.4 with CentOS. I ran yum update and CentOS upgraded itself to 3.6. However, this broke cgi-bin scripts for all of the domains on the server (giving "Internal Server Error" with "Premature end of script headers" in the log files). It looks like the upgrade replaced Plesk's suexec with its own. I was able to fix this by: mv /usr/sbin/suexec /usr/sbin/suexec.old cp -p /usr/local/psa/suexec/psa-suexec /usr/sbin/suexec service httpd restart As always, use the above steps at your own risk (although this is not particularly dangerous). Other than the cgi-bin issue, no other problems with the update (so far!).