diff --git a/.forgejo/workflows/build-docker.yaml b/.forgejo/workflows/build-docker.yaml
index 14f6983..94b3744 100644
--- a/.forgejo/workflows/build-docker.yaml
+++ b/.forgejo/workflows/build-docker.yaml
@@ -16,7 +16,7 @@ jobs:
       - name: Set up Docker Buildx
         uses: docker/setup-buildx-action@v3
       - name: create-version-string
-        run: ISO_SEEDER_TAG="$(git rev-parse --short HEAD)-$(date --utc --iso-8601)"
+        run: export ISO_SEEDER_TAG="$(git rev-parse --short HEAD)-$(date --utc --iso-8601)"
       - run: echo $ISO_SEEDER_TAG
       - name: Build and push
         uses: docker/build-push-action@v6