[Solved] Fixing Apache suexec and mod_fcgid: Error Reading Data from FastCGI Server

When running PHP applications under Apache using mod_fcgid combined with suexec privilege separation, web requests may suddenly abort with HTTP 500 Internal Server Errors and the following message in Apache error logs:

Error Message: End of script output before headers: php.fcgi • mod_fcgid: error reading data from FastCGI server

Root Cause

suexec enforces strict security checks on the FastCGI wrapper script and user directory:

1. The wrapper script and parent directories must be owned exclusively by the virtual server user and group—not root or apache.
2. File permissions cannot be group-writeable (chmod 755 is required, 775 or 777 causes instant suexec rejection).
3. The target script must reside strictly inside the compiled suexec document root (e.g. /home/user/public_html).

Resolution Steps

Inspect /var/log/httpd/suexec.log to reveal the exact permission violation, and enforce correct ownership:

# Fix permissions and ownership
chown -R user:user /home/user/fcgi-bin /home/user/public_html
chmod 755 /home/user/fcgi-bin/php.fcgi
chmod 755 /home/user/public_html