diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index 6757b12..f3dc9c1 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -9,10 +9,10 @@ jobs:
         rust: [ 1.65.0 ]
 
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
 
       - name: Cache Cargo
-        uses: actions/cache@v4
+        uses: actions/cache@0057852bfaa89a56745cba8c7296529d2fc39830 # v4.3.0
         with:
           path: |
             ~/.cargo/registry
diff --git a/.github/workflows/publish.yml b/.github/workflows/publish.yml
index ed3d5fb..7a543d7 100644
--- a/.github/workflows/publish.yml
+++ b/.github/workflows/publish.yml
@@ -14,7 +14,7 @@ jobs:
 
     steps:
       - name: Checkout repository
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4.3.1
 
       - name: Crates.io authentication
         uses: rust-lang/crates-io-auth-action@b7e9a28eded4986ec6b1fa40eeee8f8f165559ec # v1.0.3