diff --git a/.github/workflows/pages.yml b/.github/workflows/pages.yml
index 2ff0f5e1d..6bfab767c 100644
--- a/.github/workflows/pages.yml
+++ b/.github/workflows/pages.yml
@@ -19,7 +19,7 @@ jobs:
     steps:
       - name: Checkout
         uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
-      - uses: docker://pandoc/core:3.1.1.0
+      - uses: docker://pandoc/core:3.9.0.0@sha256:456259758447bd2d10a996075b92014d74fea6fac52395c7b6aa08145c0f77ae
         with:
           args: >-
             --standalone --template=template.html --output=index.html README.md
diff --git a/.github/workflows/test-html.yml b/.github/workflows/test-html.yml
index d7aaf2879..8535c4694 100644
--- a/.github/workflows/test-html.yml
+++ b/.github/workflows/test-html.yml
@@ -9,7 +9,7 @@ jobs:
     steps:
       - uses: actions/checkout@de0fac2e4500dabe0009e67214ff5f5447ce83dd # v6.0.2
       - name: Generate index.html
-        uses: docker://pandoc/core:3.8.2.1@sha256:6c1440145aaa075bd9cee256343bb108d95dfe77cfaafa6475c88d1efd62c580
+        uses: docker://pandoc/core:3.9.0.0@sha256:456259758447bd2d10a996075b92014d74fea6fac52395c7b6aa08145c0f77ae
         with:
           args: >-
             --standalone --template=template.html --output=index.html README.md