diff --git a/client/src/features/editor/hooks/useMarkdownGrammer.ts b/client/src/features/editor/hooks/useMarkdownGrammer.ts
index e6fb2eac..a3f5e714 100644
--- a/client/src/features/editor/hooks/useMarkdownGrammer.ts
+++ b/client/src/features/editor/hooks/useMarkdownGrammer.ts
@@ -395,8 +395,13 @@ export const useMarkdownGrammer = ({
           const selection = window.getSelection();
           if (!selection) return;
           const currentContent = currentBlock.crdt.read();
+          const currentCaret = getAbsoluteCaretPosition(e.currentTarget);
           const markdownElement = checkMarkdownPattern(currentContent);
-          if (markdownElement && currentBlock.type === "p") {
+          if (
+            markdownElement &&
+            currentCaret === markdownElement.length &&
+            currentBlock.type === "p"
+          ) {
             e.preventDefault();
             // 마크다운 패턴 매칭 시 타입 변경하고 내용 비우기
             currentBlock.type = markdownElement.type;
diff --git a/client/src/features/editor/utils/domSyncUtils.ts b/client/src/features/editor/utils/domSyncUtils.ts
index 53a4a4b9..fb5f4f5a 100644
--- a/client/src/features/editor/utils/domSyncUtils.ts
+++ b/client/src/features/editor/utils/domSyncUtils.ts
@@ -139,7 +139,11 @@ const setsEqual = (a: Set<string>, b: Set<string>): boolean => {
 };
 
 const sanitizeText = (text: string): string => {
-  return text.replace(/<br>/g, "\u00A0");
+  return text
+    .replace(/<br>/g, "\u00A0")
+    .replace(/</g, "&lt;")
+    .replace(/>/g, "&gt;")
+    .replace(/&/g, "&amp;");
 };
 
 // 배열 비교 헬퍼 함수