WordPress Flash Uploader HTTP Error.

You’re on the right track — the HTTP Error during WordPress Flash uploader uploads typically points to a mod_security rule blocking the request. Flash-based uploaders (older versions of WordPress used this) often triggered false positives in web application firewalls like mod_security, leading to uploads being denied.

Correct and Improved Steps to Fix the HTTP Error with Flash Uploader

1. Create a .htaccess File in wp-admin Folder

Yes, you’re right about uploading a file in the wp-admin folder. Create a file named .htaccess (no filename, just .htaccess).

Inside .htaccess file, put:

<IfModule mod_security.c>
  SecFilterEngine Off
  SecFilterScanPOST Off
</IfModule>

💡 Note:
This disables mod_security only in the wp-admin folder — limiting the security risk.

If your hosting provider uses mod_security2, the above code might not work. Use this instead:

<IfModule mod_security2.c>
  SecRuleEngine Off
</IfModule>

2. Additional Fixes to Try (If .htaccess Didn’t Work):

✅ Increase PHP Memory Limit:

Sometimes, upload issues are caused by memory exhaustion.

In your site’s root .htaccess, add:

php_value memory_limit 256M

Increase Upload Limits:

php_value upload_max_filesize 64M
php_value post_max_size 64M
php_value max_execution_time 300
php_value max_input_time 300

Use Browser Uploader:

If you’re using an older version of WordPress that defaults to Flash, try switching to the browser uploader — there’s usually a link below the upload field.

Why Flash Uploader Has Issues:

• Flash is deprecated and unsupported in modern browsers.
• Flash uploaders often don’t send proper authentication headers (like cookies), which causes WordPress to fail the upload with an HTTP error.
• Flash is blocked by most modern security tools and hosts.

Recommended Long-Term Fix:

Upgrade WordPress to a modern version (5.3+), which uses JavaScript/HTML5 uploaders — no Flash involved, more stable and secure.