Fix: Path traversal vulnerability in guardrails endpoints

- Sanitize category_name in GET /guardrails/ui/category_yaml/{category_name}
  to reject path traversal sequences and validate resolved path stays within
  the expected categories directory.

- Add file path validation for presidio_ad_hoc_recognizers in the Presidio
  guardrail hook to prevent arbitrary JSON file reading via POST /guardrails.
  Rejects path traversal (..), enforces .json extension, and resolves symlinks.

Customer: Take2 Games

litellm/proxy/guardrails/guardrail_endpoints.py

@@ -743,6 +743,14 @@ async def get_category_yaml(category_name: str):
         The raw YAML content of the category file
     """
     import os
+    import re
+
+    # Validate category_name to prevent path traversal
+    # Only allow alphanumeric characters, hyphens, and underscores
+    if not re.match(r'^[a-zA-Z0-9_-]+$', category_name):
+        raise HTTPException(
+            status_code=400, detail="Invalid category name. Only alphanumeric characters, hyphens, and underscores are allowed."
+        )
 
     # Get the categories directory path
     categories_dir = os.path.join(
@@ -755,6 +763,14 @@ async def get_category_yaml(category_name: str):
     # Construct the file path
     category_file_path = os.path.join(categories_dir, f"{category_name}.yaml")
 
+    # Resolve to absolute path and verify it stays within categories_dir
+    resolved_path = os.path.realpath(category_file_path)
+    resolved_categories_dir = os.path.realpath(categories_dir)
+    if not resolved_path.startswith(resolved_categories_dir + os.sep):
+        raise HTTPException(
+            status_code=400, detail="Invalid category name."
+        )
+
     if not os.path.exists(category_file_path):
         raise HTTPException(
             status_code=404, detail=f"Category file not found: {category_name}"

litellm/proxy/guardrails/guardrail_hooks/presidio.py

@@ -123,6 +123,8 @@ class _OPTIONAL_PresidioPIIMasking(CustomGuardrail):
         ad_hoc_recognizers = presidio_ad_hoc_recognizers
         if ad_hoc_recognizers is not None:
             try:
+                # Sanitize file path to prevent path traversal attacks
+                ad_hoc_recognizers = self._validate_recognizer_file_path(ad_hoc_recognizers)
                 with open(ad_hoc_recognizers, "r") as file:
                     self.ad_hoc_recognizers = json.load(file)
             except FileNotFoundError:
@@ -140,6 +142,42 @@ class _OPTIONAL_PresidioPIIMasking(CustomGuardrail):
             presidio_anonymizer_api_base=presidio_anonymizer_api_base,
         )
 
+    @staticmethod
+    def _validate_recognizer_file_path(file_path: str) -> str:
+        """
+        Validate and sanitize the ad-hoc recognizers file path to prevent
+        path traversal attacks.
+
+        Ensures:
+        1. No path traversal sequences (../)
+        2. File must have .json extension
+        3. Path is resolved to absolute and checked
+        """
+        import os
+
+        # Reject paths containing path traversal sequences
+        if ".." in file_path:
+            raise ValueError(
+                f"Invalid file path: path traversal sequences are not allowed. file_path={file_path}"
+            )
+
+        # Ensure the file has a .json extension
+        if not file_path.endswith(".json"):
+            raise ValueError(
+                f"Invalid file path: only .json files are allowed. file_path={file_path}"
+            )
+
+        # Resolve to absolute path
+        resolved_path = os.path.realpath(file_path)
+
+        # Ensure resolved path still ends with .json (in case of symlink tricks)
+        if not resolved_path.endswith(".json"):
+            raise ValueError(
+                f"Invalid file path: resolved path must be a .json file. file_path={file_path}"
+            )
+
+        return resolved_path
+
     def validate_environment(
         self,
         presidio_analyzer_api_base: Optional[str] = None,