diff --git a/src/routes/op.ts b/src/routes/op.ts
index 1a02257..eda0db3 100644
--- a/src/routes/op.ts
+++ b/src/routes/op.ts
@@ -14,6 +14,7 @@ import {
   getFolder,
   getFolderByPath,
   getVideo,
+  isSafeVideoId,
   listChildFolders,
   listTopFolders,
   listVideosInFolder,
@@ -352,6 +353,14 @@ opRouter.get('/op/videos/idAvailable', requireAuth, (req, res) => {
     res.json({ ok: true, available: false, reason: '비어 있음' })
     return
   }
+  if (!isSafeVideoId(id)) {
+    res.json({
+      ok: true,
+      available: false,
+      reason: '형식: 영문/숫자/_/- (1~64자)'
+    })
+    return
+  }
   const available = !videoIdExists(id)
   res.json({ ok: true, available })
 })