The SVG spec was recently updated to remove support for data: URLs in SVG <use> element.
This improves security of the Web platform as well as compatibility between browsers as Webkit does not support data: URLs in SVG <use> element.
Reason for the removal
SVG <use> element can fetch external SVG images and clone it into the current document. This is a powerful capability, and therefore it is restricted to same-origin SVG images.
However, data: URLs are treated as same-origin resources which caused several security bugs, such as bypasses of Trusted Types and Sanitizer API.
These security bugs led to a discussion of the best approach to resolve them. And we came to a consensus among browser vendors (from Mozilla and Apple) that the best way forward is to remove support for data: URLs in SVG <use> element.
For sites which use data: URLs in SVG <use> element, there are several alternatives.
Use same-origin SVG images
You can load same-origin SVG images using <use> element.
<div class="icon">
<svg width="1em" height="1em">
<use xlink:href="svgicons.svg#user-icon"></use>
</svg>
</div>
Use inline SVG images
You can reference inline SVG images using <use> element.
<svg style="display:none" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
<defs>
<symbol id="user-icon" viewBox="0 0 32 32">
<path d="M25.333 9.335c0 5.153-4.179 9.333-9.333 9.333s-9.333-4.18-9.333-9.333c0-5.156 4.179-9.335 9.333-9.335s9.333 4.179 9.333 9.335zM23.203 18.908c-2.008 1.516-4.499 2.427-7.203 2.427-2.707 0-5.199-0.913-7.209-2.429-5.429 2.391-8.791 9.835-8.791 13.095h32c0-3.231-3.467-10.675-8.797-13.092z">
</symbol>
<!-- And potentially many more icons -->
</defs>
</svg>
<div class="icon">
<svg width="1em" height="1em">
<use xlink:href="#user-icon"></use>
</svg>
</div>
Use SVG images with blob: URLs
If you don't have control over a page's HTML or same-origin resources (such as JavaScript libraries), you can load SVG images using blob: URLs in <use> element.
const svg_content = `<svg style="display:none" version="1.1" xmlns="http://www.w3.org/2000/svg" xmlns:xlink="http://www.w3.org/1999/xlink">
<defs>
<symbol id="user-icon" viewBox="0 0 32 32">
<path d="M25.333 9.335c0 5.153-4.179 9.333-9.333 9.333s-9.333-4.18-9.333-9.333c0-5.156 4.179-9.335 9.333-9.335s9.333 4.179 9.333 9.335zM23.203 18.908c-2.008 1.516-4.499 2.427-7.203 2.427-2.707 0-5.199-0.913-7.209-2.429-5.429 2.391-8.791 9.835-8.791 13.095h32c0-3.231-3.467-10.675-8.797-13.092z">
</symbol>
<!-- And potentially many more icons -->
</defs>
</svg>`;
const blob = new Blob([svg_content], {type: 'image/svg+xml'});
const url = URL.createObjectURL(blob);
const svg = document.createElementNS('http://www.w3.org/2000/svg', 'svg');
const use = document.createElementNS('http://www.w3.org/2000/svg', 'use');
use.setAttribute('href', url + '#user-icon');
svg.appendChild(use);
document.body.appendChild(svg);
Live examples
You can find live examples for these alternatives on GitHub.