diff --git a/action.yml b/action.yml
index 31330112..242cab1c 100644
--- a/action.yml
+++ b/action.yml
@@ -212,6 +212,7 @@ runs:
       env:
         GITHUB_WORKSPACE: ${{ github.workspace }}
         GITHUB_BASE_REF: ${{ github.base_ref }}
+        GITHUB_EVENT_HEAD_REPO_FORK: ${{ github.event.pull_request.head.repo.fork }}
         # INPUT_<VARIABLE_NAME> is not available in Composite run steps
         # https://docs.github.com/en/actions/creating-actions/metadata-syntax-for-github-actions#example-specifying-inputs
         INPUT_FILES_PATTERN_FILE: ${{ steps.glob.outputs.paths-output-file }}