diff --git a/.github/workflows/mutation.yml b/.github/workflows/mutation.yml
index 9843e4c..e50c8c5 100644
--- a/.github/workflows/mutation.yml
+++ b/.github/workflows/mutation.yml
@@ -20,6 +20,9 @@ on:
 
 name: mutation test
 
+permissions:
+  contents: read
+
 jobs:
   mutation:
     uses: yiisoft/actions/.github/workflows/roave-infection.yml@master