Perl or cgi script cannot be executed: 500 Internal Server Error

Symptoms

• Perl or CGI script located inside of /var/www/vhosts/example.com/httpdocs/cgi-bin/ directory cannot be executed with the error:

  500 external Server Error

• Apache error log /var/log/httpd/error_log or domain's error log /var/www/vhosts/system/example.com/logs/error_log contain one of the following errors:

  AH02811: script not found or unable to stat: /var/www/vhosts/example.com/cgi-bin

  [client 203.0.113.2:55719] End of script output before headers: script.pl

  [client 203.0.113.2:55719] End of script output before headers: script.cgi

• The error below can be found in suexec.log:

  • on CentOS/RHEL-based distributions at: /var/log/httpd/suexec.log

  • on Debian/Ubuntu-based distributions at: /var/log/apache2/suexec.log

  uid: (10000/johndoe) gid: (1003/1003) cmd: script.pl
  target uid/gid (10000/1003 or 1002) mismatch with directory (10000/1003) or program (0/0)

Cause

Incorrect permissions are set for /var/www/vhosts/example.com/httpdocs/cgi-bin/script.pl file or entire /var/www/vhosts/example.com/httpdocs/cgi-bin/ directory.

Resolution

1. Connect to the server using SSH

2. Find the system user of the subscription example.com:

   # plesk db -Ne "select su.login from domains d, hosting h, sys_users su where d.id=h.dom_id and h.sys_user_id=su.id and d.name='example.com';"
   johndoe

3. Set correct permissions and ownership for the directory and script with the system user obtained on the previous step:

   # chown -R johndoe:psacln /var/www/vhosts/example.com/httpdocs/cgi-bin

   # chmod ug+x /var/www/vhosts/example.com/httpdocs/cgi-bin/script.pl

   Note:script.pl should be changed to the real cgi or perl script name.

4. Only if issue is not fixed, apply the following to restore default permissions for the domain:

   # plesk repair fs example.com