PHP File upload failed (Request Entity Too Large)

Symptoms

• When uploading a file in PHP, one of the following errors will appear in the Apache logs:

  CONFIG_TEXT: ModSecurity: Request body (Content-Length) is larger than
  the configured limit (134217728).

  CONFIG_TEXT: ModSecurity: Output filter: Content-Length (529160) over the limit (524288). 

• WordPress will also receive the 403 response in the website's PHP domain access_log file:

  CONFIG_TEXT: POST /wp-admin/async-upload.php HTTP/1.1" 403

• Another error that could appear on the website page is:

  CONFIG_TEXT: Request Entity Too Large
  The requested resource does not allow request data with GET requests,
  or the amount of data provided in the request exceeds the capacity limit.
  Additionally, a 413 Request Entity Too Large error was encountered
  while trying to use an ErrorDocument to handle the request.

   

Cause

cPanel installs Mod_Security via EasyApache by default to increase web security. Mod_security has a default setting to block large requests to prevent DoS attacks and other security risks.

Two of the most common causes are the following settings:

• SecRequestBodyLimit
• SecResponseBodyLimit

Note: More details can be found in the Documentation pages:
Mod_Security rules reference page for version 2.x

Resolution

Increase the SecRequestBodyLimit and/or SecResponseBodyLimit in the configuration file.

1. How to log into server using SSH?
2. Edit file /etc/apache2/conf.d/modsec/modsec2.user.conf

3. Set the limits for the following settings:

   Set SecRequestBodyLimit, SecResponseBodyLimit, and/or SecRequestBodyNoFilesLimit to a value higher than the default limits, for example:

   Note: This file is usually empty by default. You will need to edit the existing value or add a new line to set the custom value.

   CONFIG_TEXT: SecRequestBodyLimit 546870912
   SecResponseBodyLimit 5242880
   SecRequestBodyNoFilesLimit 10485760

4. Save the file, then restart Apache.

   # /scripts/restartsrv_httpd

   After restarting Apache, refresh the webpage and then try the upload once more.

Additional Resources

If you need to adjust the php.ini upload settings, please review the related article below to assist with this task.

How to increase the maximum file upload size limit in PHP