diff --git a/.github/workflows/tests.yml b/.github/workflows/tests.yml
index 835accf..1f6c3c6 100644
--- a/.github/workflows/tests.yml
+++ b/.github/workflows/tests.yml
@@ -6,6 +6,9 @@ on:
     branches:
       - master
 
+permissions:
+  contents: read
+
 jobs:
   tests:
     name: tests on ${{ matrix.python-version }}
@@ -19,10 +22,12 @@ jobs:
 
     steps:
       - name: Checkout
-        uses: actions/checkout@v3
+        uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
+        with:
+          persist-credentials: false
 
       - name: Install python
-        uses: actions/setup-python@v4
+        uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6.2.0
         with:
           python-version: ${{ matrix.python-version }}