diff --git a/.github/workflows/build.yaml b/.github/workflows/build.yaml
index be677bcceef..9950f7173e0 100644
--- a/.github/workflows/build.yaml
+++ b/.github/workflows/build.yaml
@@ -13,7 +13,7 @@ jobs:
       - name: Install dependencies
         run: sudo apt update && sudo apt install -y uncrustify
       - name: Checkout OpenVPN
-        uses: actions/checkout@v4
+        uses: actions/checkout@eef61447b9ff4aafe5dcd4e0bbf5d482be7e7871 # v4
         with:
           path: openvpn
       - name: Show uncrustify version
@@ -27,7 +27,7 @@ jobs:
       - name: Show changes on standard output
         run: git diff
         working-directory: openvpn
-      - uses: actions/upload-artifact@v4
+      - uses: actions/upload-artifact@b4b15b8c7c6ac21ea08fcf65892d2ee8f75cf882 # v4
         with:
           name: uncrustify-changes.patch
           path: 'openvpn/uncrustify-changes.patch'
@@ -49,7 +49,7 @@ jobs:
       - name: Install dependencies
         run: sudo apt update && sudo apt install -y mingw-w64 unzip cmake ninja-build build-essential wget python3-docutils man2html-base
       - name: Checkout OpenVPN
-        uses: actions/checkout@v4
+        uses: actions/checkout@eef61447b9ff4aafe5dcd4e0bbf5d482be7e7871 # v4
 
       - name: Restore from cache and install vcpkg
         uses: lukka/run-vcpkg@v11
@@ -64,7 +64,7 @@ jobs:
           buildPreset: mingw-${{ matrix.arch }}
           buildPresetAdditionalArgs: "['--config Debug']"
 
-      - uses: actions/upload-artifact@v4
+      - uses: actions/upload-artifact@b4b15b8c7c6ac21ea08fcf65892d2ee8f75cf882 # v4
         with:
           name: openvpn-mingw-${{ matrix.arch }}
           path: |
@@ -72,7 +72,7 @@ jobs:
             ${{ github.workspace }}/out/build/mingw/${{ matrix.arch }}/Debug/*.dll
             !${{ github.workspace }}/out/build/mingw/${{ matrix.arch }}/Debug/test_*.exe
 
-      - uses: actions/upload-artifact@v4
+      - uses: actions/upload-artifact@b4b15b8c7c6ac21ea08fcf65892d2ee8f75cf882 # v4
         with:
           name: openvpn-mingw-${{ matrix.arch }}-tests
           path: |
@@ -91,7 +91,7 @@ jobs:
     name: "mingw unittest ${{ matrix.test }} - ${{ matrix.arch }} - OSSL"
     steps:
       - name: Retrieve mingw unittest
-        uses: actions/download-artifact@v4
+        uses: actions/download-artifact@fa0a91b85d4f404e444e00e005971372dc801d16 # v4
         with:
           name: openvpn-mingw-${{ matrix.arch }}-tests
           path: unittests
@@ -151,7 +151,7 @@ jobs:
       - name: Install dependencies
         run: sudo apt update && sudo apt install -y liblzo2-dev libpam0g-dev liblz4-dev libcap-ng-dev libnl-genl-3-dev linux-libc-dev man2html libcmocka-dev python3-docutils libtool automake autoconf ${SSLPKG}
       - name: Checkout OpenVPN
-        uses: actions/checkout@v4
+        uses: actions/checkout@eef61447b9ff4aafe5dcd4e0bbf5d482be7e7871 # v4
       - name: autoconf
         run: autoreconf -fvi
       - name: configure
@@ -178,7 +178,7 @@ jobs:
       - name: Install dependencies
         run: sudo apt update && sudo apt install -y liblzo2-dev libpam0g-dev liblz4-dev libcap-ng-dev libnl-genl-3-dev linux-libc-dev man2html clang libcmocka-dev python3-docutils libtool automake autoconf libmbedtls-dev
       - name: Checkout OpenVPN
-        uses: actions/checkout@v4
+        uses: actions/checkout@eef61447b9ff4aafe5dcd4e0bbf5d482be7e7871 # v4
       - name: autoconf
         run: autoreconf -fvi
       - name: configure
@@ -237,7 +237,7 @@ jobs:
       - name: Install dependencies
         run: brew install openssl@1.1 openssl@3 lzo lz4 man2html cmocka libtool automake autoconf libressl
       - name: Checkout OpenVPN
-        uses: actions/checkout@v4
+        uses: actions/checkout@eef61447b9ff4aafe5dcd4e0bbf5d482be7e7871 # v4
       - name: autoconf
         run: autoreconf -fvi
       - name: configure
@@ -259,7 +259,7 @@ jobs:
 
       runs-on: windows-latest
       steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@eef61447b9ff4aafe5dcd4e0bbf5d482be7e7871 # v4
       - uses: lukka/get-cmake@latest
 
       - name: Install rst2html
@@ -286,7 +286,7 @@ jobs:
           buildPreset: win-${{ matrix.arch }}-release
           testPreset: win-${{ matrix.arch }}-release
 
-      - uses: actions/upload-artifact@v4
+      - uses: actions/upload-artifact@b4b15b8c7c6ac21ea08fcf65892d2ee8f75cf882 # v4
         with:
           name: openvpn-msvc-${{ matrix.arch }}
           path: |
@@ -326,7 +326,7 @@ jobs:
       - name: Install dependencies
         run: sudo apt update && sudo apt install -y liblzo2-dev libpam0g-dev liblz4-dev linux-libc-dev man2html clang libcmocka-dev python3-docutils libtool automake autoconf pkg-config libcap-ng-dev libnl-genl-3-dev
       - name: "libressl: checkout"
-        uses: actions/checkout@v4
+        uses: actions/checkout@eef61447b9ff4aafe5dcd4e0bbf5d482be7e7871 # v4
         with:
           path: libressl
           repository: libressl/portable
@@ -346,7 +346,7 @@ jobs:
       - name: "ldconfig"
         run: sudo ldconfig
       - name: Checkout OpenVPN
-        uses: actions/checkout@v4
+        uses: actions/checkout@eef61447b9ff4aafe5dcd4e0bbf5d482be7e7871 # v4
       - name: autoconf
         run: autoreconf -fvi
       - name: configure
diff --git a/.github/workflows/coverity-scan.yml b/.github/workflows/coverity-scan.yml
index 37b8102eb21..a20ac033bb1 100644
--- a/.github/workflows/coverity-scan.yml
+++ b/.github/workflows/coverity-scan.yml
@@ -13,7 +13,7 @@ jobs:
     steps:
       - name: Check submission cache
         id: check_submit
-        uses: actions/cache/restore@v4
+        uses: actions/cache/restore@3624ceb22c1c5a301c8db4169662070a689d9ea8 # v4
         with:
           path: |
             cov-int
@@ -25,7 +25,7 @@ jobs:
 
       - name: Checkout OpenVPN
         if: steps.check_submit.outputs.cache-hit != 'true'
-        uses: actions/checkout@v4
+        uses: actions/checkout@eef61447b9ff4aafe5dcd4e0bbf5d482be7e7871 # v4
 
       - name: Download Coverity Build Tool
         if: steps.check_submit.outputs.cache-hit != 'true'
@@ -65,7 +65,7 @@ jobs:
 
       - name: Cache submission
         if: steps.check_submit.outputs.cache-hit != 'true'
-        uses: actions/cache/save@v4
+        uses: actions/cache/save@3624ceb22c1c5a301c8db4169662070a689d9ea8 # v4
         with:
           path: |
             cov-int