diff --git a/.github/workflows/mypy.yml b/.github/workflows/mypy.yml
index 4d3c5c9e8..c68e798fa 100644
--- a/.github/workflows/mypy.yml
+++ b/.github/workflows/mypy.yml
@@ -25,7 +25,7 @@ jobs:
 
       - name: Get changed files
         id: changed-files
-        uses: tj-actions/changed-files@v46.0.1
+        uses: tj-actions/changed-files@b2d17c0ca3e4ff20b0ae4b84f93228223b51b8d5 # v46.0.1 (pinned to commit hash for security)
 
       - name: Filter Python files
         id: filter-python