diff --git a/build-constraints.yaml b/build-constraints.yaml
index 73b9b4e1..b7a4c714 100644
--- a/build-constraints.yaml
+++ b/build-constraints.yaml
@@ -2513,7 +2513,7 @@ packages:
         - flac
         - flac-picture
         - forma
-        - ghc-syntax-highlighter
+        - ghc-syntax-highlighter < 0 # https://github.com/mrkkrp/ghc-syntax-highlighter/issues/14
         - hspec-megaparsec
         - htaglib
         - html-entity-map
@@ -2522,8 +2522,8 @@ packages:
         - megaparsec
         - megaparsec-tests
         - mmark
-        - mmark-cli
-        - mmark-ext
+        - mmark-cli < 0 # via ghc-syntax-highlighter
+        - mmark-ext < 0 # via ghc-syntax-highlighter
         - modern-uri
         - pagination
         - parser-combinators