diff --git a/server/validation.ts b/server/validation.ts
index 4243a1f48..2a21ad1f2 100644
--- a/server/validation.ts
+++ b/server/validation.ts
@@ -18,7 +18,7 @@ export const assertArray = (value: unknown, message?: string) => {
 
 export const assertIn = (
   value: string,
-  options: (string | null)[],
+  options: (string | undefined | null)[],
   message?: string
 ) => {
   if (!options.includes(value)) {