diff --git a/build-constraints.yaml b/build-constraints.yaml
index 4b21a05d..f0f8f9e6 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -3042,7 +3042,7 @@ packages:
         - doctemplates
         - emojis
         - pandoc
-        - citeproc
+        - citeproc < 0.5 # https://github.com/commercialhaskell/stackage/issues/6171
         - commonmark
         - commonmark-extensions
         - commonmark-pandoc