diff --git a/.github/workflows/ci.yml b/.github/workflows/ci.yml
index a1347724da6..4dcae6d29b5 100644
--- a/.github/workflows/ci.yml
+++ b/.github/workflows/ci.yml
@@ -1,6 +1,9 @@
 name: Run unit tests
 
 on: [push, pull_request]
+permissions:
+  contents: read
+
 jobs:
   lint:
     name: Check PHP syntax
@@ -42,6 +45,8 @@ jobs:
       - run: |
           git ls-files | grep \\\.php$ | grep -v ^dictionaries/scripts/* | ./vendor/bin/parallel-lint --stdin
   chunk-matrix:
+    permissions:
+      contents: none
     name: Generate Chunk Matrix
 
     runs-on: ubuntu-latest
diff --git a/.github/workflows/shepherd.yml b/.github/workflows/shepherd.yml
index 1ff14195871..b60bca06d65 100644
--- a/.github/workflows/shepherd.yml
+++ b/.github/workflows/shepherd.yml
@@ -2,6 +2,9 @@ name: Run Shepherd
 
 on: [push, pull_request]
 
+permissions:
+  contents: read
+
 jobs:
   build:
     runs-on: ubuntu-latest
diff --git a/.github/workflows/windows-ci.yml b/.github/workflows/windows-ci.yml
index dc5fd77c560..b901fcdf8fc 100644
--- a/.github/workflows/windows-ci.yml
+++ b/.github/workflows/windows-ci.yml
@@ -2,8 +2,13 @@ name: Run unit tests on Windows
 
 on: [push, pull_request]
 
+permissions:
+  contents: read
+
 jobs:
   chunk-matrix:
+    permissions:
+      contents: none
     name: Generate Chunk Matrix
 
     runs-on: ubuntu-latest