diff --git a/.changeset/giant-bugs-battle.md b/.changeset/giant-bugs-battle.md
new file mode 100644
index 000000000..89d0a605b
--- /dev/null
+++ b/.changeset/giant-bugs-battle.md
@@ -0,0 +1,5 @@
+---
+'astro': patch
+---
+
+Fix: markdown "require is not defined" issue
diff --git a/packages/astro/src/core/create-vite.ts b/packages/astro/src/core/create-vite.ts
index a70ff3ede..07d73733f 100644
--- a/packages/astro/src/core/create-vite.ts
+++ b/packages/astro/src/core/create-vite.ts
@@ -21,6 +21,8 @@ const ALWAYS_EXTERNAL = new Set([
 	'@sveltejs/vite-plugin-svelte',
 	'micromark-util-events-to-acorn',
 	'@astrojs/markdown-remark',
+	// in-lined for markdown modules
+	'github-slugger',
 	'node-fetch',
 	'prismjs',
 	'shiki',