diff --git a/build-constraints.yaml b/build-constraints.yaml
index 595b99f7..3c05ba4d 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -841,7 +841,7 @@ packages:
         - ghc-lib-parser
 
     "Shayne Fletcher <shayne.fletcher@digitalasset.com>":
-        - ghc-lib-parser-ex
+        - ghc-lib-parser-ex < 9.0.0.5 # https://github.com/commercialhaskell/stackage/issues/6369
 
     "Karl Ostmo <kostmo@gmail.com> @kostmo":
         - perfect-hash-generator