diff --git a/build-constraints.yaml b/build-constraints.yaml
index baae1426..794bc192 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -3955,7 +3955,7 @@ packages:
         - ascii
         - ascii-case
         - ascii-caseless
-        - ascii-char
+        - ascii-char < 1.0.1 # https://github.com/commercialhaskell/stackage/issues/6832
         - ascii-group
         - ascii-numbers
         - ascii-predicates