diff --git a/build-constraints.yaml b/build-constraints.yaml
index dd82d36f..4e09aedf 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -3895,7 +3895,7 @@ packages:
     "Dan Firth <dan.firth@homotopic.tech> @locallycompact":
         - shake-plus
         - within
-        
+
     "Domen Kozar <domen@enlambda.com> @domenkozar":
         - elm2nix
         - mixpanel-client
@@ -4862,6 +4862,9 @@ packages:
       # https://github.com/commercialhaskell/stackage/issues/5393
       - aeson < 1.5.0.0
 
+      # https://github.com/commercialhaskell/stackage/issues/5421
+      - hosc < 0.18
+
 # end of packages
 
 # Package flags are applied to individual packages, and override the values of