diff --git a/packages/vite/src/node/plugins/css.ts b/packages/vite/src/node/plugins/css.ts
index 6e5ba2e06ec2df..142a696662f5e3 100644
--- a/packages/vite/src/node/plugins/css.ts
+++ b/packages/vite/src/node/plugins/css.ts
@@ -623,7 +623,7 @@ export function cssPostPlugin(config: ResolvedConfig): Plugin {
     },
 
     augmentChunkHash(chunk) {
-      if (chunk.viteMetadata.importedCss.size) {
+      if (chunk.viteMetadata?.importedCss.size) {
         let hash = ''
         for (const id of chunk.viteMetadata.importedCss) {
           hash += id