diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 95876a8a..58755fcf 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -34,7 +34,7 @@ jobs:
         include:
           # Note: Specifying the version of valgrind and cargo-binstall is not supported.
           - os: ubuntu-20.04
-            tool: cargo-hack@0.5.24,cargo-llvm-cov@0.5.2,cargo-minimal-versions@0.1.8,parse-changelog@0.5.2,cargo-udeps@0.1.35,cargo-valgrind@2.1.0,cargo-deny@0.13.5,cross@0.2.4,nextest@0.9.11,protoc@3.21.12,shellcheck@0.9.0,shfmt@3.6.0,wasm-pack@0.10.3,wasmtime@3.0.1,mdbook@0.4.22,mdbook-linkcheck@0.7.7,cargo-watch@8.1.1
+            tool: cargo-hack@0.5.24,cargo-llvm-cov@0.5.2,cargo-minimal-versions@0.1.8,parse-changelog@0.5.2,cargo-udeps@0.1.35,cargo-valgrind@2.1.0,cargo-deny@0.13.5,cross@0.2.4,nextest@0.9.11,protoc@3.21.12,shellcheck@0.9.0,shfmt@3.6.0,wasm-pack@0.10.3,wasmtime@3.0.1,mdbook@0.4.23,mdbook-linkcheck@0.7.7,cargo-watch@8.1.1
           # Nextest supports basic version ranges as well. For other tools, this will be supported by https://github.com/taiki-e/install-action/pull/27.
           - os: ubuntu-20.04
             tool: nextest@0.9
diff --git a/CHANGELOG.md b/CHANGELOG.md
index 6dec0504..3742d1f6 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -10,6 +10,8 @@ Note: In this file, do not use the hard wrap in the middle of a sentence for com
 
 ## [Unreleased]
 
+- Update `mdbook@latest` to 0.4.23.
+
 ## [1.17.0] - 2022-12-14
 
 - Update `protoc@latest` to 3.21.12.
diff --git a/main.sh b/main.sh
index a91826fa..a7259c9d 100755
--- a/main.sh
+++ b/main.sh
@@ -591,7 +591,7 @@ for tool in "${tools[@]}"; do
             ;;
         mdbook)
             # https://github.com/rust-lang/mdBook/releases
-            latest_version="0.4.22"
+            latest_version="0.4.23"
             repo="rust-lang/mdBook"
             case "${version}" in
                 latest) version="${latest_version}" ;;