diff --git a/build-constraints.yaml b/build-constraints.yaml
index 8029450e..e8be8793 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -1219,7 +1219,7 @@ packages:
         - di-df1
         - di-handle
         - di-monad
-        - exinst
+        - exinst < 0 # via serialize and cborg https://github.com/commercialhaskell/stackage/issues/3666 and 3667
         - flay
         - network-simple
         - network-simple-tls
@@ -1228,10 +1228,10 @@ packages:
         - pipes-binary
         - pipes-network
         - pipes-network-tls
-        - safe-money
+        - safe-money < 0 # via serialise https://github.com/commercialhaskell/stackage/issues/3666
         - vector-bytes-instances
         - xmlbf-xeno
-        - xmlbf-xmlhtml
+        - xmlbf-xmlhtml < 0 # GHC 8.4 via xmlhtml via hspec-2.5.0
         - xmlbf
 
     "Tomas Carnecky @wereHamster":