27 November 2025

How SVG logo uploads started failing with HTTP error in WordPress and the MIME type + server resource steps that fixed it

Web administrators and designers who frequently use WordPress may notice occasional hiccups with uploading different file types—one such issue involves uploading SVG logos. Scenarios where everything worked fine yesterday suddenly become problematic after minor updates or server changes. An increasingly common challenge arises when trying to upload an SVG logo to the WordPress media library and being met with an “HTTP error” message. This article will walk you through how this issue starts, why it happens, and how to resolve it by dealing with MIME type restrictions and server resource settings.

TLDR: Too Long, Didn’t Read

SVG uploads may start failing in WordPress due to unsupported MIME types or server configuration limits. The problem often comes after a WordPress core update or a change in hosting. Fixing it involves allowing the proper MIME type for SVG in WordPress and making server adjustments such as increasing memory limits. With a few simple code changes and server-side tweaks, SVG upload functionality can be fully restored.

Understanding the Problem: Why SVG Uploads Fail

Scalable Vector Graphics (SVG) files are a preferred format for logos because of their infinite scalability and small file size. However, WordPress does not allow SVG uploads by default due to potential security risks, as SVGs can contain malicious JavaScript code. While many users find ways to override this restriction and allow safe uploads, these customizations can break after updates or under certain server configurations.

The issue often manifests itself as an “HTTP error” during uploading, which is a rather vague message. In the background, the real problem may be one of the following:

• The server does not recognize SVG files due to missing MIME type declaration.
• Security plugins or WordPress itself are blocking SVG uploads as a precaution.
• The server runs out of available memory or execution time during the upload.

Step 1: Allowing SVG MIME Type in WordPress

The first step toward a fix is making sure WordPress recognizes SVG as a valid file type. To do this, you can add a filter to your theme’s functions.php file or in a custom plugin.

function add_svg_upload_mime_type( $mimes ) {
    $mimes['svg'] = 'image/svg+xml';
    return $mimes;
}
add_filter( 'upload_mimes', 'add_svg_upload_mime_type' );

This piece of code tells WordPress to allow uploads of `.svg` files by explicitly permitting the image/svg+xml MIME type. Once added and saved, try uploading the SVG file again.

However, allowing SVG files isn’t enough. It’s essential to sanitize them to prevent XSS vulnerabilities. Use a plugin like “Safe SVG” for this, which handles MIME types and file sanitization in one go.

Step 2: Fixing HTTP Errors from Server Limitations

Even after allowing the correct MIME type, you may still encounter HTTP errors. This can happen due to file size limitations or exhausted server resources. Most servers have default limits that might be too low for certain image uploads, even with SVGs.

Try addressing the issue with the following methods:

1. Increase PHP Memory Limit

• Edit your wp-config.php and add the following:

  define('WP_MEMORY_LIMIT', '256M');

2. Raise Upload File Size in php.ini

Access your hosting panel and edit your php.ini file to increase the maximum file size for uploads:

upload_max_filesize = 16M
post_max_size = 20M
memory_limit = 256M
max_execution_time = 300

3. Modify .htaccess for Apache Servers

If you’re on an Apache server, add the following lines to your .htaccess file:

php_value upload_max_filesize 16M
php_value post_max_size 20M
php_value memory_limit 256M
php_value max_execution_time 300
php_value max_input_time 300

After applying the above changes, restart the server if possible, especially in cases involving php.ini or .htaccess settings.

Step 3: Troubleshooting with Plugins

Sometimes security plugins or file management tools interfere with file uploads. If SVG files are still not uploading after following the above steps, try deactivating the following temporarily:

• Security plugins like Wordfence or iThemes Security
• Caching plugins like W3 Total Cache
• Media optimization plugins

Once you’ve isolated the interfering plugin, review its settings. Many security plugins have options to block unknown file extensions or restrict file upload types.

The Role of Web Hosts and Server Configurations

Sometimes the issue doesn’t lie within WordPress itself, but in the server’s configuration. Shared hosting services might disable SVG uploads entirely for safety reasons. Contact your hosting provider if you continue facing errors, asking them specifically if SVG MIME types are supported and if there are any server-side limitations.

A few hosting environments also use mod_security rules that blanket-block specific file extensions, including SVG. In such cases, you either need to:

• Request mod_security rule adjustments from your host
• Move to a more customizable hosting plan such as VPS

Conclusion

SVG upload problems often snowball from simple MIME type restrictions to more complex server-side constraints. Understanding the root cause—whether it’s a WordPress limitation, plugin conflict, MIME type rejection, or server memory cap—is crucial in finding a lasting solution. With the right configurations and security awareness, SVG uploads can be safely enabled, giving logos and icons crisp scalability without weighty image files.

FAQs

Why can’t I upload SVG files to WordPress by default?

WordPress disables SVG uploads out of the box due to potential security vulnerabilities from embedded scripts in SVG files.

Is SVG safe to use in WordPress?

Yes, if sanitized correctly. Use plugins like “Safe SVG” to clean uploaded files and reduce risk.

What does the “HTTP error” mean during uploads?

It’s a generic message that can occur for numerous reasons, including unsupported file types, insufficient server memory, or timeouts during upload.

What MIME type should I use for SVG uploads?

The proper MIME type for SVG files is image/svg+xml.

How can I permanently fix SVG uploads in WordPress?

Enable SVG support by adjusting the MIME type in your functions.php file, sanitize uploads using a plugin, and ensure your server settings allow for sufficient memory and file size limits.

Do hosting providers block SVG uploads?

Some shared hosting environments do restrict SVG uploads due to security policies. Contact your host or upgrade to a plan with more control to resolve this.