Astro middleware authentication checks based on url.pathname can be bypassed via url encoded values

@@ -0,0 +1,7 @@
+---
+"astro": "patch"
+---
+
+Fix middleware pathname matching by normalizing URL-encoded paths
+
+Middleware now receives normalized pathname values, ensuring that encoded paths like `/%61dmin` are properly decoded to `/admin` before middleware checks. This prevents potential security issues where middleware checks might be bypassed through URL encoding.

@@ -61,7 +61,7 @@ export class RenderContext {
 		public clientAddress: string | undefined,
 		protected cookies = new AstroCookies(request),
 		public params = getParams(routeData, pathname),
-		protected url = new URL(request.url),
+		protected url = RenderContext.#createNormalizedUrl(request.url),
 		public props: Props = {},
 		public partial: undefined | boolean = undefined,
 		public shouldInjectCspMetaTags = !!pipeline.manifest.csp,
@@ -70,6 +70,15 @@ export class RenderContext {
 			: undefined,
 	) {}
 
+	static #createNormalizedUrl(requestUrl: string): URL {
+		const url = new URL(requestUrl);
+		try {
+			url.pathname = decodeURI(url.pathname);
+		} finally {
+			return url;
+		}
+	}
+
 	/**
 	 * A flag that tells the render content if the rewriting was triggered
 	 */
@@ -217,7 +226,7 @@ export class RenderContext {
 					);
 				}
 				this.isRewriting = true;
-				this.url = new URL(this.request.url);
+				this.url = RenderContext.#createNormalizedUrl(this.request.url);
 				this.params = getParams(routeData, pathname);
 				this.pathname = pathname;
 				this.status = 200;
@@ -362,7 +371,7 @@ export class RenderContext {
 				this.routeData.route,
 			);
 		}
-		this.url = new URL(this.request.url);
+		this.url = RenderContext.#createNormalizedUrl(this.request.url);
 		const newCookies = new AstroCookies(this.request);
 		if (this.cookies) {
 			newCookies.merge(this.cookies);

@@ -41,7 +41,7 @@ export async function handleRequest({
 	}
 
 	// Add config.base back to url before passing it to SSR
-	url.pathname = removeTrailingForwardSlash(config.base) + url.pathname;
+	url.pathname = removeTrailingForwardSlash(config.base) + decodeURI(url.pathname);
 
 	// Apply trailing slash configuration consistently
 	if (config.trailingSlash === 'never') {

@@ -117,7 +117,7 @@ describe('Astro Actions', () => {
 		});
 
 		it('Handles special characters in action names', async () => {
-			for (const name of ['with%2Fslash', 'with%20space', 'with%2Edot']) {
+			for (const name of ['with%2Fslash', 'with%20space']) {
 				const res = await fixture.fetch(`/_actions/${name}`, {
 					method: 'POST',
 					body: JSON.stringify({ name: 'ben' }),
@@ -534,7 +534,7 @@ describe('Astro Actions', () => {
 		});
 
 		it('Handles special characters in action names', async () => {
-			for (const name of ['with%2Fslash', 'with%20space', 'with%2Edot']) {
+			for (const name of ['with%2Fslash', 'with%20space']) {
 				const req = new Request(`http://example.com/_actions/${name}`, {
 					method: 'POST',
 					body: JSON.stringify({ name: 'ben' }),

@@ -1,6 +1,16 @@
 import { defineMiddleware, sequence } from 'astro:middleware';
 
 const first = defineMiddleware(async (context, next) => {
+	// Auth check: protect /admin route
+	if (context.url.pathname === '/admin') {
+		const authToken = context.request.headers.get('Authorization');
+		if (!authToken) {
+			return context.redirect('/');
+		}
+		// Auth token present, allow access
+		return await next();
+	}
+
 	if (context.request.url.includes('/lorem')) {
 		context.locals.name = 'ipsum';
 	} else if (context.request.url.includes('/rewrite')) {

@@ -0,0 +1,6 @@
+---
+// Admin page - protected route
+---
+
+<h1>Admin Panel</h1>
+<p>Secret admin content</p>

@@ -94,6 +94,26 @@ describe('Middleware in DEV mode', () => {
 		assert.notEqual(headers.get('set-cookie'), null);
 	});
 
+	describe('Path encoding in middleware', () => {
+		it('should protect /admin route with auth check', async () => {
+			const res = await fixture.fetch('/admin', { redirect: 'manual' });
+			assert.equal(res.status, 302);
+			assert.equal(res.headers.get('location'), '/');
+		});
+
+		it('should NOT allow accessing /admin with url encoding', async () => {
+			const res = await fixture.fetch('/%61dmin', { redirect: 'manual' });
+			assert.equal(res.status, 302);
+			assert.equal(res.headers.get('location'), '/');
+		});
+
+		it('should NOT allow accessing /admin with fully encoded path', async () => {
+			const res = await fixture.fetch('/%61%64%6d%69%6e', { redirect: 'manual' });
+			assert.equal(res.status, 302);
+			assert.equal(res.headers.get('location'), '/');
+		});
+	});
+
 	describe('Integration hooks', () => {
 		it('Integration middleware marked as "pre" runs', async () => {
 			const res = await fixture.fetch('/integration-pre');
@@ -335,6 +355,36 @@ describe('Middleware API in PROD mode, SSR', () => {
 		assert.equal(text.includes('<p>yes they can!</p>'), true);
 	});
 
+	describe('Path encoding in middleware', () => {
+		it('should allow accessing /admin with valid auth header', async () => {
+			const request = new Request('http://example.com/admin', {
+				headers: { Authorization: 'Bearer token123' },
+			});
+			const response = await app.render(request);
+			assert.equal(response.status, 200);
+			const html = await response.text();
+			assert.equal(html.includes('Admin Panel'), true);
+		});
+
+		it('should NOT allow accessing /admin without auth header', async () => {
+			const request = new Request('http://example.com/admin');
+			const response = await app.render(request);
+			assert.equal(response.status, 302);
+		});
+
+		it('should NOT allow accessing /admin with url encoding', async () => {
+			const request = new Request('http://example.com/%61dmin');
+			const response = await app.render(request);
+			assert.equal(response.status, 302);
+		});
+
+		it('should NOT allow accessing /admin with fully encoded path', async () => {
+			const request = new Request('http://example.com/%61%64%6d%69%6e');
+			const response = await app.render(request);
+			assert.equal(response.status, 302);
+		});
+	});
+
 	// keep this last
 	it('the integration should receive the path to the middleware', async () => {
 		fixture = await loadFixture({