diff --git a/build-constraints.yaml b/build-constraints.yaml
index aa6d6555..87815ce9 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -2805,6 +2805,9 @@ packages:
         - servant-swagger < 1.1.2.1
         - servant-mock < 0.8.1.2
 
+        # https://github.com/fpco/stackage/issues/2259
+        - megaparsec < 5.2.0
+
 # end of packages
 
 # Package flags are applied to individual packages, and override the values of