diff --git a/poetry.lock b/poetry.lock
index 9c19f124..dce1a824 100644
--- a/poetry.lock
+++ b/poetry.lock
@@ -48,6 +48,7 @@ description = "Security oriented static analyser for python code."
 optional = false
 python-versions = ">=3.9"
 groups = ["lint"]
+markers = "python_version == \"3.9\""
 files = [
     {file = "bandit-1.8.6-py3-none-any.whl", hash = "sha256:3348e934d736fcdb68b6aa4030487097e23a501adf3e7827b63658df464dddd0"},
     {file = "bandit-1.8.6.tar.gz", hash = "sha256:dbfe9c25fc6961c2078593de55fd19f2559f9e45b99f1272341f5b95dea4e56b"},
@@ -67,6 +68,33 @@ test = ["beautifulsoup4 (>=4.8.0)", "coverage (>=4.5.4)", "fixtures (>=3.0.0)",
 toml = ["tomli (>=1.1.0) ; python_version < \"3.11\""]
 yaml = ["PyYAML"]
 
+[[package]]
+name = "bandit"
+version = "1.9.2"
+description = "Security oriented static analyser for python code."
+optional = false
+python-versions = ">=3.10"
+groups = ["lint"]
+markers = "python_version >= \"3.10\""
+files = [
+    {file = "bandit-1.9.2-py3-none-any.whl", hash = "sha256:bda8d68610fc33a6e10b7a8f1d61d92c8f6c004051d5e946406be1fb1b16a868"},
+    {file = "bandit-1.9.2.tar.gz", hash = "sha256:32410415cd93bf9c8b91972159d5cf1e7f063a9146d70345641cd3877de348ce"},
+]
+
+[package.dependencies]
+colorama = {version = ">=0.3.9", markers = "platform_system == \"Windows\""}
+PyYAML = ">=5.3.1"
+rich = "*"
+stevedore = ">=1.20.0"
+tomli = {version = ">=1.1.0", optional = true, markers = "python_version < \"3.11\" and extra == \"toml\""}
+
+[package.extras]
+baseline = ["GitPython (>=3.1.30)"]
+sarif = ["jschema-to-python (>=1.2.3)", "sarif-om (>=1.0.4)"]
+test = ["beautifulsoup4 (>=4.8.0)", "coverage (>=4.5.4)", "fixtures (>=3.0.0)", "flake8 (>=4.0.0)", "pylint (==1.9.4)", "stestr (>=2.5.0)", "testscenarios (>=0.5.0)", "testtools (>=2.3.0)"]
+toml = ["tomli (>=1.1.0) ; python_version < \"3.11\""]
+yaml = ["PyYAML"]
+
 [[package]]
 name = "black"
 version = "25.9.0"
@@ -4093,4 +4121,4 @@ grpc = ["grpcio", "ni-grpcdevice-v1-proto", "ni-protobuf-types", "protobuf"]
 [metadata]
 lock-version = "2.1"
 python-versions = ">=3.9,<4.0"
-content-hash = "8a0ef6f263a2c3129e9a514045da9db4a17281da92d9b8ad24e91c9f97f00814"
+content-hash = "3597a298003d0ad183a815aabcdea5868848992210fbbf13e80842388ddd7005"
diff --git a/pyproject.toml b/pyproject.toml
index 8b1e2190..9dd1782e 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -73,7 +73,8 @@ grpcio-tools = [
   { version = "1.67.0", python = ">=3.13,<3.14" },
   { version = "1.75.1", python = "^3.14" },
 ]
-mypy-protobuf = ">=3.4"
+# mypy-protobuf 3.6 is the last version that supports protobuf v4.
+mypy-protobuf = ">=3.4,<3.7"
 
 [tool.poetry.group.docs]
 optional = true