diff --git a/components/content/ContentCode.vue b/components/content/ContentCode.vue
index 7b034b3c..b4d2f61c 100644
--- a/components/content/ContentCode.vue
+++ b/components/content/ContentCode.vue
@@ -18,5 +18,6 @@ const highlighted = computed(() => {
 </script>
 
 <template>
-  <pre class="code-block" v-html="highlighted" />
+  <pre v-if="lang" class="code-block" v-html="highlighted" />
+  <pre v-else class="code-block">{{ raw }}</pre>
 </template>
diff --git a/composables/shiki.ts b/composables/shiki.ts
index a35e55d5..f316d24c 100644
--- a/composables/shiki.ts
+++ b/composables/shiki.ts
@@ -48,10 +48,22 @@ export function useShikiTheme() {
   return useColorMode().value === 'dark' ? 'vitesse-dark' : 'vitesse-light'
 }
 
+const HTML_ENTITIES = {
+  '<': '&lt;',
+  '>': '&gt;',
+  '&': '&amp;',
+  '\'': '&apos;',
+  '"': '&quot;',
+} as Record<string, string>
+
+function escapeHtml(text: string) {
+  return text.replace(/[<>&'"]/g, ch => HTML_ENTITIES[ch])
+}
+
 export function highlightCode(code: string, lang: Lang) {
   const shiki = useHightlighter(lang)
   if (!shiki)
-    return code
+    return escapeHtml(code)
 
   return shiki.codeToHtml(code, {
     lang,
diff --git a/tests/__snapshots__/content-rich.test.ts.snap b/tests/__snapshots__/content-rich.test.ts.snap
index 97725153..07c1f655 100644
--- a/tests/__snapshots__/content-rich.test.ts.snap
+++ b/tests/__snapshots__/content-rich.test.ts.snap
@@ -1,9 +1,36 @@
 // Vitest Snapshot v1
 
-exports[`content-rich > block with backticks 1`] = `"<p><pre>[(\`number string) (\`tag string)]</pre></p>"`;
+exports[`content-rich > block with backticks 1`] = `"<p><pre class=\\"code-block\\">[(\`number string) (\`tag string)]</pre></p>"`;
+
+exports[`content-rich > block with injected html, with a known language 1`] = `
+"<pre>
+        <code class=\\"language-js\\">
+          &lt;a href=&quot;javascript:alert(1)&quot;&gt;click me&lt;/a&gt;
+        </code>
+      </pre>
+"
+`;
+
+exports[`content-rich > block with injected html, with an unknown language 1`] = `
+"<pre>
+        <code class=\\"language-xyzzy\\">
+          &lt;a href=&quot;javascript:alert(1)&quot;&gt;click me&lt;/a&gt;
+        </code>
+      </pre>
+"
+`;
+
+exports[`content-rich > block with injected html, without language 1`] = `
+"<pre>
+        <code>
+          &lt;a href=&quot;javascript:alert(1)&quot;&gt;click me&lt;/a&gt;
+        </code>
+      </pre>
+"
+`;
 
 exports[`content-rich > code frame 1`] = `
-"<p>Testing code block</p><p></p><p><pre lang=\\"ts\\">import { useMouse, usePreferredDark } from &#39;@vueuse/core&#39;
+"<p>Testing code block</p><p></p><p><pre class=\\"code-block\\">import { useMouse, usePreferredDark } from &apos;@vueuse/core&apos;
 // tracks mouse position
 const { x, y } = useMouse()
 // is the user prefers dark theme
@@ -20,14 +47,14 @@ exports[`content-rich > code frame 2 1`] = `
     ></a
   ></span>
   Testing<br />
-  <pre lang=\\"ts\\">const a = hello</pre>
+  <pre class=\\"code-block\\">const a = hello</pre>
 </p>
 "
 `;
 
-exports[`content-rich > code frame empty 1`] = `"<p><pre></pre><br></p>"`;
+exports[`content-rich > code frame empty 1`] = `"<p><pre class=\\"code-block\\"></pre><br></p>"`;
 
-exports[`content-rich > code frame no lang 1`] = `"<p><pre>hello world</pre><br>no lang</p>"`;
+exports[`content-rich > code frame no lang 1`] = `"<p><pre class=\\"code-block\\">hello world</pre><br>no lang</p>"`;
 
 exports[`content-rich > custom emoji 1`] = `
 "Daniel Roe
@@ -75,7 +102,7 @@ exports[`content-rich > handles formatting from servers 1`] = `
 exports[`content-rich > handles html within code blocks 1`] = `
 "<p>
   HTML block code:<br />
-  <pre lang=\\"html\\">
+  <pre class=\\"code-block\\">
 &lt;span class=&quot;icon--noto icon--noto--1st-place-medal&quot;&gt;&lt;/span&gt;
 &lt;span class=&quot;icon--noto icon--noto--2nd-place-medal-medal&quot;&gt;&lt;/span&gt;</pre
   >
diff --git a/tests/content-rich.test.ts b/tests/content-rich.test.ts
index 97d2b8f0..6b4a94e3 100644
--- a/tests/content-rich.test.ts
+++ b/tests/content-rich.test.ts
@@ -136,6 +136,39 @@ describe('content-rich', () => {
       "
     `)
   })
+
+  it ('block with injected html, without language', async () => {
+    const { formatted } = await render(`
+      <pre>
+        <code>
+          &lt;a href="javascript:alert(1)">click me&lt;/a>
+        </code>
+      </pre>
+    `)
+    expect(formatted).toMatchSnapshot()
+  })
+
+  it ('block with injected html, with an unknown language', async () => {
+    const { formatted } = await render(`
+      <pre>
+        <code class="language-xyzzy">
+          &lt;a href="javascript:alert(1)">click me&lt;/a>
+        </code>
+      </pre>
+    `)
+    expect(formatted).toMatchSnapshot()
+  })
+
+  it ('block with injected html, with a known language', async () => {
+    const { formatted } = await render(`
+      <pre>
+        <code class="language-js">
+          &lt;a href="javascript:alert(1)">click me&lt;/a>
+        </code>
+      </pre>
+    `)
+    expect(formatted).toMatchSnapshot()
+  })
 })
 
 async function render(content: string, options?: ContentParseOptions) {
@@ -173,23 +206,11 @@ vi.mock('~/composables/dialog.ts', () => {
   return {}
 })
 
-vi.mock('~/components/content/ContentCode.vue', () => {
+vi.mock('shiki-es', async (importOriginal) => {
+  const mod = await importOriginal()
   return {
-    default: defineComponent({
-      props: {
-        code: {
-          type: String,
-          required: true,
-        },
-        lang: {
-          type: String,
-        },
-      },
-      setup(props) {
-        const raw = computed(() => decodeURIComponent(props.code).replace(/&#39;/g, '\''))
-        return () => h('pre', { lang: props.lang }, raw.value)
-      },
-    }),
+    ...(mod as any),
+    setCDN() {},
   }
 })
 
diff --git a/vitest.config.ts b/vitest.config.ts
index 413bb3f7..ac4388d7 100644
--- a/vitest.config.ts
+++ b/vitest.config.ts
@@ -14,7 +14,9 @@ export default defineConfig({
     'process.client': 'true',
   },
   plugins: [
-    Vue(),
+    Vue({
+      reactivityTransform: true,
+    }),
     AutoImport({
       dts: false,
       imports: [