diff --git a/.forgejo/workflows/images.yml b/.forgejo/workflows/images.yml
index 4095e84..940ce02 100644
--- a/.forgejo/workflows/images.yml
+++ b/.forgejo/workflows/images.yml
@@ -29,7 +29,7 @@ jobs:
             echo "tag=latest" >> $GITHUB_OUTPUT
           else
             # renovate creates sub branches with `/`; these break the tagging in the build process
-            echo "tag=${{ github.ref_name }}" | sed 's/[^a-zA-Z0-9._-]/_/g' >> $GITHUB_OUTPUT
+            echo tag=$(echo "${{ github.ref_name }}" | sed 's/[^a-zA-Z0-9._-]/_/g') >> $GITHUB_OUTPUT
           fi
 
       - name: Build web image