diff --git a/libs/core/langchain_core/indexing/api.py b/libs/core/langchain_core/indexing/api.py
index 63226ba366a6f..ab729314cfc99 100644
--- a/libs/core/langchain_core/indexing/api.py
+++ b/libs/core/langchain_core/indexing/api.py
@@ -36,14 +36,14 @@
 
 def _hash_string_to_uuid(input_string: str) -> uuid.UUID:
     """Hashes a string and returns the corresponding UUID."""
-    hash_value = hashlib.sha1(input_string.encode("utf-8")).hexdigest()
+    hash_value = hashlib.sha1(input_string.encode("utf-8")).hexdigest()  # noqa: S324
     return uuid.uuid5(NAMESPACE_UUID, hash_value)
 
 
 def _hash_nested_dict_to_uuid(data: dict[Any, Any]) -> uuid.UUID:
     """Hashes a nested dictionary and returns the corresponding UUID."""
     serialized_data = json.dumps(data, sort_keys=True)
-    hash_value = hashlib.sha1(serialized_data.encode("utf-8")).hexdigest()
+    hash_value = hashlib.sha1(serialized_data.encode("utf-8")).hexdigest()  # noqa: S324
     return uuid.uuid5(NAMESPACE_UUID, hash_value)
 
 
diff --git a/libs/core/langchain_core/prompts/string.py b/libs/core/langchain_core/prompts/string.py
index 0040f4b712279..f9128147e2b1a 100644
--- a/libs/core/langchain_core/prompts/string.py
+++ b/libs/core/langchain_core/prompts/string.py
@@ -97,7 +97,8 @@ def _get_jinja2_variables_from_template(template: str) -> set[str]:
             "Please install it with `pip install jinja2`."
         )
         raise ImportError(msg) from e
-    env = Environment()
+    # noqa for insecure warning elsewhere
+    env = Environment()  # noqa: S701
     ast = env.parse(template)
     variables = meta.find_undeclared_variables(ast)
     return variables
diff --git a/libs/core/langchain_core/runnables/graph_mermaid.py b/libs/core/langchain_core/runnables/graph_mermaid.py
index 2c8319f027bf0..b0e7f3dd5de5e 100644
--- a/libs/core/langchain_core/runnables/graph_mermaid.py
+++ b/libs/core/langchain_core/runnables/graph_mermaid.py
@@ -331,7 +331,7 @@ def _render_mermaid_using_api(
     image_url = (
         f"https://mermaid.ink/img/{mermaid_syntax_encoded}?bgColor={background_color}"
     )
-    response = requests.get(image_url)
+    response = requests.get(image_url, timeout=10)
     if response.status_code == 200:
         img_bytes = response.content
         if output_file_path is not None:
diff --git a/libs/core/pyproject.toml b/libs/core/pyproject.toml
index 4a26b7f35a16f..92c0b0659ae38 100644
--- a/libs/core/pyproject.toml
+++ b/libs/core/pyproject.toml
@@ -72,6 +72,7 @@ select = [
     "PIE",
     "Q",
     "RSE",
+    "S", # https://docs.astral.sh/ruff/rules/#flake8-bandit-s
     "SIM",
     "SLOT",
     "T10",
@@ -85,6 +86,9 @@ ignore = [
     "COM812", # Messes with the formatter
     "UP007",  # Incompatible with pydantic + Python 3.9
     "W293",   # 
+    "S101",   # allow assert - TODO remove
+    "S110",   # allow try/except/pass - TODO remove
+    "S112",   # allow try/except/continue - TODO remove
 ]
 
 [tool.coverage.run]
@@ -128,12 +132,13 @@ classmethod-decorators = [
 "tests/unit_tests/prompts/test_chat.py" = ["E501"]
 "tests/unit_tests/runnables/test_runnable.py" = ["E501"]
 "tests/unit_tests/runnables/test_graph.py" = ["E501"]
+"tests/**" = ["S"]                                       # Ignore flake8-bandit rules in tests
+"scripts/**" = ["S"]                                     # Ignore flake8-bandit rules in scripts
 
 [tool.poetry.group.lint.dependencies]
 ruff = "^0.5"
 
 
-
 [tool.poetry.group.typing.dependencies]
 mypy = ">=1.10,<1.11"
 types-pyyaml = "^6.0.12.2"
@@ -142,14 +147,12 @@ types-jinja2 = "^2.11.9"
 simsimd = "^5.0.0"
 
 
-
 [tool.poetry.group.dev.dependencies]
 jupyter = "^1.0.0"
 setuptools = "^67.6.1"
 grandalf = "^0.8"
 
 
-
 [tool.poetry.group.test.dependencies]
 pytest = "^7.3.0"
 freezegun = "^1.2.2"
@@ -169,17 +172,14 @@ version = "^1.26.0"
 python = ">=3.12"
 
 
-
 [tool.poetry.group.test_integration.dependencies]
 
 
-
 [tool.poetry.group.typing.dependencies.langchain-text-splitters]
 path = "../text-splitters"
 develop = true
 
 
-
 [tool.poetry.group.test.dependencies.langchain-standard-tests]
 path = "../standard-tests"
 develop = true
diff --git a/libs/core/scripts/check_imports.py b/libs/core/scripts/check_imports.py
index 825bea5b48737..fa189a7117534 100644
--- a/libs/core/scripts/check_imports.py
+++ b/libs/core/scripts/check_imports.py
@@ -10,7 +10,8 @@
     for file in files:
         try:
             module_name = "".join(
-                random.choice(string.ascii_letters) for _ in range(20)
+                random.choice(string.ascii_letters)
+                for _ in range(20)  # noqa: S311
             )
             SourceFileLoader(module_name, file).load_module()
         except Exception: