diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 81635d6..bc48220 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -27,7 +27,7 @@ jobs:
       - uses: actions/checkout@v7
       - uses: actions/setup-go@v7
         with:
-          go-version: stable
+          go-version: 1.27.1
       - if: runner.os != 'Windows'
         uses: ruby/setup-ruby@v1
         with:
@@ -62,7 +62,7 @@ jobs:
       - uses: actions/checkout@v7
       - uses: actions/setup-go@v7
         with:
-          go-version: stable
+          go-version: 1.27.1
       - run: go env GOARCH && go test ./...
 
   arch-qemu:
@@ -80,7 +80,7 @@ jobs:
       - uses: actions/checkout@v7
       - uses: actions/setup-go@v7
         with:
-          go-version: stable
+          go-version: 1.27.1
       - run: sudo apt-get update && sudo apt-get install -y qemu-user-static
       - name: Test under qemu (${{ matrix.goarch }})
         run: GOARCH=${{ matrix.goarch }} go test -exec=${{ matrix.qemu }} ./...
@@ -96,6 +96,6 @@ jobs:
       - uses: actions/checkout@v7
       - uses: actions/setup-go@v7
         with:
-          go-version: stable
+          go-version: 1.27.1
       - name: Build ${{ matrix.goos }}/wasm
         run: GOOS=${{ matrix.goos }} GOARCH=wasm go build ./...
diff --git a/go.mod b/go.mod
index 5c344b3..cefadb5 100644
--- a/go.mod
+++ b/go.mod
@@ -1,3 +1,3 @@
 module github.com/go-ruby-msgpack/msgpack
 
-go 1.26.4
+go 1.27.1