Skip to content

fix: handle relative URLs in WebSocket domain filter #765

New issue

Have a question about this project? Sign up for a free GitHub account to open an issue and contact its maintainers and the community.

Sign up for GitHub

By clicking “Sign up for GitHub”, you agree to our terms of service and privacy statement. We’ll occasionally send you account related emails.

Already on GitHub? Sign in to your account

Open
Jah-yee wants to merge 1 commit into
base: main
Choose a base branch
from
+7 −2
Open

fix: handle relative URLs in WebSocket domain filter #765

Changes from all commits
Commits
Show all changes
1 commit
Select commit
File filter

Filter by extension

Filter by extension
Conversations
Failed to load comments.
Loading
Jump to
Jump to file
Failed to load files.
Loading
Diff view
Diff view
9 changes: 7 additions & 2 deletions src/domain-filter.ts
View file
Open in desktop
Original file line number Diff line number Diff line change
Expand Up @@ -51,8 +51,13 @@ export function buildWebSocketFilterScript(allowedDomains: string[]): string {
}
function _checkUrl(url) {
try {
var parsed = new URL(url);
return _isDomainAllowed(parsed.hostname);
// Handle relative URLs (e.g., /__webpack_hmr) by resolving against page origin
var fullUrl = url;
if (url.startsWith('/') || url.startsWith('.')) {
fullUrl = location.origin + url;
}
var parsed = new URL(fullUrl);
return parsed.hostname ? _isDomainAllowed(parsed.hostname) : true;
Comment on lines +54 to +60
Copy link
Contributor

@vercel vercel bot Mar 13, 2026

Choose a reason for hiding this comment

The reason will be displayed to describe this comment to others. Learn more.

Suggested change
// Handle relative URLs (e.g., /__webpack_hmr) by resolving against page origin
var fullUrl = url;
if (url.startsWith('/') || url.startsWith('.')) {
fullUrl = location.origin + url;
}
var parsed = new URL(fullUrl);
return parsed.hostname ? _isDomainAllowed(parsed.hostname) : true;
var parsed = new URL(url, location.origin);
return parsed.hostname ? _isDomainAllowed(parsed.hostname) : false;

Two bugs in _checkUrl: manual URL string concatenation produces invalid URLs for relative paths starting with ., and hostless URLs (data:, blob:) bypass the domain filter entirely.

Fix on Vercel

} catch(e) {
return false;
}
Expand Down