diff --git a/build-constraints.yaml b/build-constraints.yaml
index 8ba34786..6b2e00ac 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -2603,6 +2603,9 @@ packages:
 
         # https://github.com/fpco/stackage/issues/1972
         - lens < 4.15 # Re-enable `lens' benchmarks when lifted
+
+        # https://github.com/simonmar/alex/issues/94
+        - alex < 3.2.0
 # end of packages
 
 
@@ -3128,3 +3131,4 @@ tell-me-when-its-released:
 - point-octree-0.5.5.3 # If this closes https://github.com/fpco/stackage/issues/1902 we can also resolve https://github.com/fpco/lts-haskell/issues/27
 - servant-mock-0.8.1 # disabled per https://github.com/haskell-servant/servant-mock/issues/3
 - wreq 0.4.1.0
+- alex 3.2.0