diff --git a/.github/workflows/build_container.yaml b/.github/workflows/build_container.yaml
index 5797d310..3f269ed8 100644
--- a/.github/workflows/build_container.yaml
+++ b/.github/workflows/build_container.yaml
@@ -40,7 +40,7 @@ jobs:
 
       - name: Extract branch name
         id: extract_branch
-        uses: keptn/gh-action-extract-branch-name@main
+        uses: keptn/gh-action-extract-branch-name@6ca4fe061da10c66b2d7341fd1fb12962ad911b2 # main
 
       - name: Get current date and time
         id: get_datetime
diff --git a/.github/workflows/release.yaml b/.github/workflows/release.yaml
index b65b8480..6c1f631e 100644
--- a/.github/workflows/release.yaml
+++ b/.github/workflows/release.yaml
@@ -41,7 +41,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - name: Free Disk Space (Ubuntu)
-        uses: jlumbroso/free-disk-space@main
+        uses: jlumbroso/free-disk-space@54081f138730dfa15788a46383842cd2f914a1be # main
         with:
           # this might remove tools that are actually needed,
           # if set to "true" but frees about 6 GB