diff --git a/pyproject.toml b/pyproject.toml
index 24dfbe698..caa301d18 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -140,9 +140,11 @@ pinecone = [
 ]
 graphdb = [
   "SPARQLWrapper",
+  "rdflib!=6.3.2", # GPL-2.0-only license issue
 ]
 inmemorygraph = [
   "SPARQLWrapper",
+  "rdflib!=6.3.2", # GPL-2.0-only license issue
 ]
 opensearch = [
   "opensearch-py>=2",