diff --git a/packages/elements-core/src/components/MarkdownViewer/CustomComponents/ReactRouterLink.spec.tsx b/packages/elements-core/src/components/MarkdownViewer/CustomComponents/ReactRouterLink.spec.tsx
new file mode 100644
index 000000000..a0fa5ecc3
--- /dev/null
+++ b/packages/elements-core/src/components/MarkdownViewer/CustomComponents/ReactRouterLink.spec.tsx
@@ -0,0 +1,15 @@
+import { render, screen } from '@testing-library/react';
+import * as React from 'react';
+
+import { ReactRouterMarkdownLink } from './ReactRouterLink';
+
+describe('ReactRouterMarkdownLink', () => {
+  it('renders a mailto href as an external link', () => {
+    render(<ReactRouterMarkdownLink href="mailto:team@example.com">Contact</ReactRouterMarkdownLink>);
+
+    const link = screen.getByRole('link', { name: 'Contact' });
+    expect(link).toHaveAttribute('href', 'mailto:team@example.com');
+    expect(link).toHaveAttribute('target', '_blank');
+    expect(link).toHaveAttribute('rel', 'noreferrer noopener');
+  });
+});
diff --git a/packages/elements-core/src/components/MarkdownViewer/CustomComponents/ReactRouterLink.tsx b/packages/elements-core/src/components/MarkdownViewer/CustomComponents/ReactRouterLink.tsx
index d9a3560c8..8453bc917 100644
--- a/packages/elements-core/src/components/MarkdownViewer/CustomComponents/ReactRouterLink.tsx
+++ b/packages/elements-core/src/components/MarkdownViewer/CustomComponents/ReactRouterLink.tsx
@@ -1,7 +1,7 @@
 import type { LinkProps } from '@stoplight/mosaic';
 import React from 'react';
 
-const externalRegex = new RegExp('^(?:[a-z]+:)?//', 'i');
+const externalRegex = new RegExp('^(?:[a-z][a-z0-9+.-]*:|//)', 'i');
 
 export const ReactRouterMarkdownLink = ({
   title,