diff --git a/.github/workflows/ci.yaml b/.github/workflows/ci.yaml
index 6e633ca..4ed6d54 100644
--- a/.github/workflows/ci.yaml
+++ b/.github/workflows/ci.yaml
@@ -1,17 +1,21 @@
 name: tests
 on: [push, pull_request]
 
+permissions:
+  contents: read
+
 jobs:
   lint-mypy:
     name: Lint, Mypy
     runs-on: ubuntu-latest
+    timeout-minutes: 10
     strategy:
       matrix:
         python-version: ["3.8", "3.9", "3.10", "3.11"]
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
       - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v6
+        uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6
         with:
           python-version: ${{ matrix.python-version }}
       - name: Install dependencies
@@ -23,14 +27,15 @@ jobs:
   tests:
     name: Tests
     runs-on: ${{ matrix.os }}
+    timeout-minutes: 15
     strategy:
       matrix:
         os: [ubuntu-latest]
         python-version: ["3.8", "3.9", "3.10", "3.11"]
     steps:
-      - uses: actions/checkout@v6
+      - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6
       - name: Set up Python ${{ matrix.python-version }}
-        uses: actions/setup-python@v6
+        uses: actions/setup-python@a309ff8b426b58ec0e2a45f0f869d46889d02405 # v6
         with:
           python-version: ${{ matrix.python-version }}
       - name: Install dependencies
@@ -38,7 +43,7 @@ jobs:
       - name: Test with pytest and generate coverage file
         run: tox -e py
       - name: Upload coverage report to codecov
-        uses: codecov/codecov-action@v6
+        uses: codecov/codecov-action@57e3a136b779b570ffcdbf80b3bdc90e7fab3de2 # v6
         if: success()
         with:
           file: coverage.xml