diff --git a/pyproject.toml b/pyproject.toml
index 012f8b7..b9426f4 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -15,7 +15,7 @@ authors = [{name = "GetYourGuide GmbH"}]
 requires-python = ">=3.10,<4.0"
 
 dependencies = [
-    "marshmallow==4.2.0",
+    "marshmallow==4.2.1",
     "marshmallow-dataclass==8.7.1",
     "click==8.1.8",
     "PyYAML==6.0.3",
diff --git a/uv.lock b/uv.lock
index 62beb7b..5123326 100644
--- a/uv.lock
+++ b/uv.lock
@@ -33,7 +33,7 @@ requires-dist = [
     { name = "click", specifier = "==8.1.8" },
     { name = "coverage", marker = "extra == 'dev'", specifier = ">=7.0.0" },
     { name = "cryptography", specifier = ">=45.0.0" },
-    { name = "marshmallow", specifier = "==4.2.0" },
+    { name = "marshmallow", specifier = "==4.2.1" },
     { name = "marshmallow-dataclass", specifier = "==8.7.1" },
     { name = "pre-commit", marker = "extra == 'dev'", specifier = ">=4.0.0" },
     { name = "pygithub", specifier = "==2.8.1" },
@@ -520,15 +520,15 @@ wheels = [
 
 [[package]]
 name = "marshmallow"
-version = "4.2.0"
+version = "4.2.1"
 source = { registry = "https://pypi.org/simple" }
 dependencies = [
     { name = "backports-datetime-fromisoformat", marker = "python_full_version < '3.11'" },
     { name = "typing-extensions", marker = "python_full_version < '3.11'" },
 ]
-sdist = { url = "https://files.pythonhosted.org/packages/bc/34/55d47aab1ef03fb5aab96257a31acfc58791d274cf86c044e6e75e6d3bfe/marshmallow-4.2.0.tar.gz", hash = "sha256:908acabd5aa14741419d3678d3296bda6abe28a167b7dcd05969ceb8256943ac", size = 221225, upload-time = "2026-01-04T16:07:36.921Z" }
+sdist = { url = "https://files.pythonhosted.org/packages/d8/61/9540e1b120e9eff74b24def6060b79347f2b4083dddbd5a435f6e8d74b14/marshmallow-4.2.1.tar.gz", hash = "sha256:4d1d66189c8d279ca73a6b0599d74117e5f8a3830b5cd766b75c2bb08e3464e7", size = 221309, upload-time = "2026-01-23T13:00:24.841Z" }
 wheels = [
-    { url = "https://files.pythonhosted.org/packages/1c/b6/0a907f92c2158c9841da0227c7074ce1490f578f34d67cbba82ba8f9146e/marshmallow-4.2.0-py3-none-any.whl", hash = "sha256:1dc369bd13a8708a9566d6f73d1db07d50142a7580f04fd81e1c29a4d2e10af4", size = 48448, upload-time = "2026-01-04T16:07:34.269Z" },
+    { url = "https://files.pythonhosted.org/packages/6c/41/e8cfdebc3a475c397e074ceaa12e86dca1b23e8e10c2ab4d4875f9a01418/marshmallow-4.2.1-py3-none-any.whl", hash = "sha256:d82b1a83cfbb4667d050850fbed4e9d4435576cb95f5ff37894f375dce201768", size = 48451, upload-time = "2026-01-23T13:00:23.009Z" },
 ]
 
 [[package]]