diff --git a/.github/workflows/markdown-link-check.yml b/.github/workflows/markdown-link-check.yml
index 538d8a27..db52d7a6 100644
--- a/.github/workflows/markdown-link-check.yml
+++ b/.github/workflows/markdown-link-check.yml
@@ -6,8 +6,8 @@ jobs:
   check:
     runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
       # upstream issue, https://github.com/tcort/markdown-link-check/issues/196
-      - uses: gaurav-nelson/github-action-markdown-link-check@1.0.15
+      - uses: gaurav-nelson/github-action-markdown-link-check@d53a906aa6b22b8979d33bc86170567e619495ec # 1.0.15
         with:
           config-file: '.github/workflows/markdown.links.config.json'
diff --git a/.github/workflows/misspell.yml b/.github/workflows/misspell.yml
index 695b0c7b..9531899d 100644
--- a/.github/workflows/misspell.yml
+++ b/.github/workflows/misspell.yml
@@ -11,8 +11,8 @@ jobs:
   misspell:
     runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
       - name: misspell
-        uses: reviewdog/action-misspell@v1
+        uses: reviewdog/action-misspell@18ffb61effb93b47e332f185216be7e49592e7e1 # v1
         with:
           locale: "US"
diff --git a/.github/workflows/notfound.yml b/.github/workflows/notfound.yml
index 5ed3c2f2..cdda58ee 100644
--- a/.github/workflows/notfound.yml
+++ b/.github/workflows/notfound.yml
@@ -9,8 +9,8 @@ jobs:
   check:
     runs-on: ubuntu-24.04
     steps:
-      - uses: actions/checkout@v4
+      - uses: actions/checkout@11bd71901bbe5b1630ceea73d27597364c9af683 # v4
       - name: Fix links
-        uses: tmcw/notfoundbot@v2.3.1
+        uses: tmcw/notfoundbot@f91be597e4a7e2a182788b1c5ffdc460df3195ea # v2.3.1
         env:
           GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}