diff --git a/.github/workflows/check_on_different_r_os.yml b/.github/workflows/check_on_different_r_os.yml
index 2e692b64..d3df397b 100644
--- a/.github/workflows/check_on_different_r_os.yml
+++ b/.github/workflows/check_on_different_r_os.yml
@@ -32,20 +32,20 @@ jobs:
       GITHUB_PAT: ${{ secrets.GITHUB_TOKEN }}
 
     steps:
-      - uses: actions/checkout@v3
+      - uses: actions/checkout@f43a0e5ff2bd294095638e18286ca9a3d1956744 # v3
 
-      - uses: r-lib/actions/setup-r@v2
+      - uses: r-lib/actions/setup-r@d3c5be51b12e724e68f33216ca3c148b66d5f0b6 # v2
         with:
           r-version: ${{ matrix.config.r }}
           extra-repositories: https://inbo.r-universe.dev
 
-      - uses: r-lib/actions/setup-pandoc@v2
+      - uses: r-lib/actions/setup-pandoc@d3c5be51b12e724e68f33216ca3c148b66d5f0b6 # v2
 
-      - uses: r-lib/actions/setup-r-dependencies@v2
+      - uses: r-lib/actions/setup-r-dependencies@d3c5be51b12e724e68f33216ca3c148b66d5f0b6 # v2
         with:
           extra-packages: any::rcmdcheck
           needs: check
 
-      - uses: r-lib/actions/check-r-package@v2
+      - uses: r-lib/actions/check-r-package@d3c5be51b12e724e68f33216ca3c148b66d5f0b6 # v2
         with:
           error-on: '"error"'
diff --git a/.github/workflows/examples.yml b/.github/workflows/examples.yml
index 7fe04c0d..b1513157 100644
--- a/.github/workflows/examples.yml
+++ b/.github/workflows/examples.yml
@@ -14,7 +14,7 @@ jobs:
     name: "test Rmd"
     steps:
       - name: checkout
-        uses: actions/checkout@v4
+        uses: actions/checkout@34e114876b0b11c390a56381ad16ebd13914f8d5 # v4
       - name: build examples
         uses: inbo/actions/render_inbomd@devel
         env: