diff --git a/build-constraints.yaml b/build-constraints.yaml
index 28d76545..fa15b2e9 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -7375,6 +7375,9 @@ packages:
         - persistent-qq < 2.12.0.3
         - persistent-test < 2.13.1.3
 
+        # https://github.com/commercialhaskell/stackage/issues/6551
+        - hpack < 0.35
+
 # end of packages
 
 # Package flags are applied to individual packages, and override the values of