diff --git a/plugins/code-syntax-highlight/src/renderers/toHTMLRenderers.ts b/plugins/code-syntax-highlight/src/renderers/toHTMLRenderers.ts
index bb8bf495c5..e43158142d 100644
--- a/plugins/code-syntax-highlight/src/renderers/toHTMLRenderers.ts
+++ b/plugins/code-syntax-highlight/src/renderers/toHTMLRenderers.ts
@@ -1,6 +1,7 @@
 import type { MdNode, CodeBlockMdNode } from '@toast-ui/editor';
 import type { HTMLToken } from '@toast-ui/toastmark';
 import { PrismJs } from '@t/index';
+import { escapeXml } from '@/utils/common';
 
 const BACKTICK_COUNT = 3;
 
@@ -17,6 +18,7 @@ export function getHTMLRenderers(prism: PrismJs) {
       }
 
       let content = node.literal!;
+      let contentEscaped = false;
 
       if (infoWords.length && infoWords[0].length) {
         const [lang] = infoWords;
@@ -28,9 +30,12 @@ export function getHTMLRenderers(prism: PrismJs) {
 
         if (registeredLang) {
           content = prism.highlight(node.literal!, registeredLang, lang);
+          contentEscaped = true;
         }
       }
 
+      content = contentEscaped ? content : escapeXml(content);
+
       return [
         { type: 'openTag', tagName: 'pre', classNames: preClasses },
         { type: 'openTag', tagName: 'code', attributes: codeAttrs },
diff --git a/plugins/code-syntax-highlight/src/utils/common.ts b/plugins/code-syntax-highlight/src/utils/common.ts
index 0646d3a8fb..0f224167f0 100644
--- a/plugins/code-syntax-highlight/src/utils/common.ts
+++ b/plugins/code-syntax-highlight/src/utils/common.ts
@@ -1,3 +1,28 @@
 export function flatten<T>(arr: T[]): T[] {
   return arr.reduce<T[]>((a, b) => a.concat(Array.isArray(b) ? flatten(b) : b), []);
 }
+
+const XMLSPECIAL = '[&<>"]';
+const reXmlSpecial = new RegExp(XMLSPECIAL, 'g');
+
+function replaceUnsafeChar(char: string) {
+  switch (char) {
+    case '&':
+      return '&amp;';
+    case '<':
+      return '&lt;';
+    case '>':
+      return '&gt;';
+    case '"':
+      return '&quot;';
+    default:
+      return char;
+  }
+}
+
+export function escapeXml(text: string) {
+  if (reXmlSpecial.test(text)) {
+    return text.replace(reXmlSpecial, replaceUnsafeChar);
+  }
+  return text;
+}