diff --git a/CHANGELOG.md b/CHANGELOG.md
index 0403ed4..55d2819 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -1,5 +1,9 @@
 # sapper changelog
 
+## 0.14.2
+
+* Prevent unsafe replacements ([#307](https://github.com/sveltejs/sapper/pull/307))
+
 ## 0.14.1
 
 * Route parameters can be qualified with regex characters ([#283](https://github.com/sveltejs/sapper/pull/283))
diff --git a/package.json b/package.json
index f23a3c3..8a8b7a6 100644
--- a/package.json
+++ b/package.json
@@ -1,6 +1,6 @@
 {
   "name": "sapper",
-  "version": "0.14.1",
+  "version": "0.14.2",
   "description": "Military-grade apps, engineered by Svelte",
   "main": "dist/middleware.ts.js",
   "bin": {
diff --git a/src/middleware.ts b/src/middleware.ts
index 4f23e17..dd589a8 100644
--- a/src/middleware.ts
+++ b/src/middleware.ts
@@ -355,11 +355,11 @@ function get_page_handler(routes: RouteObject[], store_getter: (req: Req) => Sto
 			}
 
 			const page = template()
-				.replace('%sapper.base%', `<base href="${req.baseUrl}/">`)
-				.replace('%sapper.scripts%', `<script>${inline_script}</script>${scripts}`)
-				.replace('%sapper.html%', html)
-				.replace('%sapper.head%', `<noscript id='sapper-head-start'></noscript>${head}<noscript id='sapper-head-end'></noscript>`)
-				.replace('%sapper.styles%', (css && css.code ? `<style>${css.code}</style>` : ''));
+				.replace('%sapper.base%', () => `<base href="${req.baseUrl}/">`)
+				.replace('%sapper.scripts%', () => `<script>${inline_script}</script>${scripts}`)
+				.replace('%sapper.html%', () => html)
+				.replace('%sapper.head%', () => `<noscript id='sapper-head-start'></noscript>${head}<noscript id='sapper-head-end'></noscript>`)
+				.replace('%sapper.styles%', () => (css && css.code ? `<style>${css.code}</style>` : ''));
 
 			res.statusCode = status;
 			res.end(page);
diff --git a/test/app/routes/unsafe-replacement.html b/test/app/routes/unsafe-replacement.html
new file mode 100644
index 0000000..98c654f
--- /dev/null
+++ b/test/app/routes/unsafe-replacement.html
@@ -0,0 +1,9 @@
+$&
+
+<script>
+	export default {
+		preload() {
+			return '$&';
+		}
+	};
+</script>
\ No newline at end of file
diff --git a/test/common/test.js b/test/common/test.js
index 79751e7..84fb55e 100644
--- a/test/common/test.js
+++ b/test/common/test.js
@@ -619,6 +619,16 @@ function run({ mode, basepath = '' }) {
 						assert.equal(name, 'BODY');
 					});
 			});
+
+			it('replaces %sapper.xxx% tags safely', () => {
+				return nightmare
+					.goto(`${base}/unsafe-replacement`)
+					.init()
+					.page.html()
+					.then(html => {
+						assert.equal(html.indexOf('%sapper'), -1);
+					});
+			});
 		});
 
 		describe('headers', () => {