diff --git a/.github/workflows/check-links-nightly.yml b/.github/workflows/check-links-nightly.yml
index dfac05d..7ff9f09 100644
--- a/.github/workflows/check-links-nightly.yml
+++ b/.github/workflows/check-links-nightly.yml
@@ -9,7 +9,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@master
-      - uses: gaurav-nelson/github-action-markdown-link-check@v1
+      - uses: gaurav-nelson/github-action-markdown-link-check@5c5dfc0ac2e225883c0e5f03a85311ec2830d368 # v1
         with:
           config-file: '.github/workflows/mlc_config.json'
           base-branch: 'main'
diff --git a/.github/workflows/check-links.yml b/.github/workflows/check-links.yml
index 4159e11..047c8e4 100644
--- a/.github/workflows/check-links.yml
+++ b/.github/workflows/check-links.yml
@@ -7,7 +7,7 @@ jobs:
     runs-on: ubuntu-latest
     steps:
       - uses: actions/checkout@master
-      - uses: gaurav-nelson/github-action-markdown-link-check@v1
+      - uses: gaurav-nelson/github-action-markdown-link-check@5c5dfc0ac2e225883c0e5f03a85311ec2830d368 # v1
         with:
           config-file: '.github/workflows/mlc_config.json'
           base-branch: 'main'