diff --git a/bucket/mdbook.json b/bucket/mdbook.json
index e9c75dab28..5af3343ec0 100644
--- a/bucket/mdbook.json
+++ b/bucket/mdbook.json
@@ -1,12 +1,12 @@
 {
-    "version": "0.4.50",
+    "version": "0.4.51",
     "description": "Create a book from markdown files.",
     "homepage": "https://github.com/rust-lang/mdBook",
     "license": "MPL-2.0",
     "architecture": {
         "64bit": {
-            "url": "https://github.com/rust-lang/mdBook/releases/download/v0.4.50/mdbook-v0.4.50-x86_64-pc-windows-msvc.zip",
-            "hash": "01d8b4d4a0b91fc8725ff17ce597fa3b428996f193a8e21cc41632939d12b485"
+            "url": "https://github.com/rust-lang/mdBook/releases/download/v0.4.51/mdbook-v0.4.51-x86_64-pc-windows-msvc.zip",
+            "hash": "23e22ce76fa8e5857ed784959390a42f9bcf5f9468233c81f71f0d1540ff9e49"
         }
     },
     "bin": "mdbook.exe",