diff --git a/build-constraints.yaml b/build-constraints.yaml
index cd89a747..0617acbd 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -420,7 +420,7 @@ packages:
         - FPretty
 
     "Maarten Faddegon <stackage@maartenfaddegon.nl> @MaartenFaddegon":
-        - libgraph
+        - libgraph < 0 # via union-find https://github.com/commercialhaskell/stackage/issues/6770
         - Hoed
 
     "Agustin Camino <agustin.camino@gmail.com> @acamino":