diff --git a/build-constraints.yaml b/build-constraints.yaml
index c5ddfb5b..545711b7 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -3408,8 +3408,8 @@ packages:
         - collect-errors
         - mixed-types-num
         - cdar-mBound
-        - aern2-mp
-        - aern2-real
+        - aern2-mp < 0 # https://github.com/commercialhaskell/stackage/issues/6648
+        - aern2-real < 0 # https://github.com/commercialhaskell/stackage/issues/6648
 
     "Bartosz Nitka <niteria@gmail.com> @niteria":
         - oeis