diff --git a/.github/workflows/publish.yml b/.github/workflows/publish.yml
index 21f57711..d1a92821 100644
--- a/.github/workflows/publish.yml
+++ b/.github/workflows/publish.yml
@@ -19,7 +19,7 @@ jobs:
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps:
       # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@ee0669bd1cc54295c223e0bb666b733df41de1c5 # v2
 
       # The same command that users can use locally is used to build documentation.
       - name: Build documentation
@@ -27,7 +27,7 @@ jobs:
 
       # Publish the result by overwriting the "gh-pages" branch with the new content.
       - name: Deploy
-        uses: JamesIves/github-pages-deploy-action@4.1.4
+        uses: JamesIves/github-pages-deploy-action@5dc1d5a192aeb5ab5b7d5a77b7d36aea4a7f5c92 # 4.1.4
         with:
           branch: gh-pages
           folder: docs
diff --git a/.github/workflows/pull.yml b/.github/workflows/pull.yml
index b9faee61..6ff65538 100644
--- a/.github/workflows/pull.yml
+++ b/.github/workflows/pull.yml
@@ -18,7 +18,7 @@ jobs:
     # Steps represent a sequence of tasks that will be executed as part of the job
     steps:
       # Checks-out your repository under $GITHUB_WORKSPACE, so your job can access it
-      - uses: actions/checkout@v2
+      - uses: actions/checkout@ee0669bd1cc54295c223e0bb666b733df41de1c5 # v2
 
       # The same command that users can use locally is used to build documentation.
       - name: Build documentation
@@ -26,7 +26,7 @@ jobs:
       
       # Publish generated site as artifact. Unfortunately viewing it requires
       # downloading a .zip and uncompressing that (https://github.com/actions/upload-artifact/issues/14#issuecomment-620728238)
-      - uses: actions/upload-artifact@v4
+      - uses: actions/upload-artifact@ea165f8d65b6e75b540449e92b4886f43607fa02 # v4
         with:
           name: html-docs
           path: docs