diff --git a/src/vs/editor/common/services/modelServiceImpl.ts b/src/vs/editor/common/services/modelServiceImpl.ts
index 736dcdef04616fb60dc05506cfbe5acf2a6c66ca..f506eef2f5c8c539c1210e3bc766f58b1e875b05 100644
--- a/src/vs/editor/common/services/modelServiceImpl.ts
+++ b/src/vs/editor/common/services/modelServiceImpl.ts
@@ -203,7 +203,7 @@ class ModelMarkerHandler {
 			}
 
 			hoverMessage.appendMarkdown(`<span style='font-family: Monaco, Menlo, Consolas, "Droid Sans Mono", "Inconsolata", "Courier New", monospace, "Droid Sans Fallback"; white-space: pre-wrap;'>`);
-			message = message.trim();
+			message = escape(message.trim());
 			const lines = message.split(/\r\n|\r|\n/g);
 			if (lines.length > 1) {
 				if (source) {