diff --git a/pyproject.toml b/pyproject.toml
index 5909919..9bde3c6 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -50,7 +50,7 @@ tests = [
   "coverage==7.5.3",
   "werkzeug==3.0.3",
   "flask==3.0.3",
-  "marshmallow==3.21.2",
+  "marshmallow==3.21.3",
   "webargs==8.4.0",
   "apispec==6.6.1",
   "PyYAML==6.0.1",