diff --git a/build-constraints.yaml b/build-constraints.yaml
index 7098cc5b..01471dd8 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -4766,6 +4766,9 @@ packages:
       # https://github.com/commercialhaskell/stackage/issues/5322
       - swagger2 < 2.6
 
+      # https://github.com/commercialhaskell/stackage/issues/5323
+      - base64-bytestring < 1.1
+
 # end of packages
 
 # Package flags are applied to individual packages, and override the values of