fix(proxy): sanitize debug request payload to prevent log injection

Strip CR/LF from JSON payload strings before verbose_proxy_logger.debug
in _debug_log_request_payload. Add _sanitize_for_log helper and unit tests.

Made-with: Cursor

litellm/proxy/common_request_processing.py

@@ -433,6 +433,13 @@ def _has_attribute_error_in_chain(exc: Exception) -> bool:
     return False
 
 
+def _sanitize_for_log(message: str) -> str:
+    """Strip line breaks from strings before logging to reduce log injection risk."""
+    if not isinstance(message, str):
+        message = str(message)
+    return message.replace("\r", "").replace("\n", " ")
+
+
 class ProxyBaseLLMRequestProcessing:
     def __init__(self, data: dict):
         self.data = data
@@ -879,9 +886,10 @@ class ProxyBaseLLMRequestProcessing:
                 type(self.data).__name__,
             )
         else:
+            _safe_payload_str = _sanitize_for_log(_payload_str)
             verbose_proxy_logger.debug(
-                "Request received by LiteLLM:\n%s",
-                _payload_str,
+                "Request received by LiteLLM: %s",
+                _safe_payload_str,
             )
 
     async def base_process_llm_request(  # noqa: PLR0915

tests/test_litellm/proxy/test_common_request_processing.py

@@ -19,12 +19,21 @@ from litellm.proxy.common_request_processing import (
     _is_azure_model_router_request,
     _override_openai_response_model,
     _parse_event_data_for_error,
+    _sanitize_for_log,
     create_response,
 )
 from litellm.proxy.dd_span_tagger import DDSpanTagger
 from litellm.proxy.utils import ProxyLogging
 
 
+class TestSanitizeForLog:
+    def test_replaces_newlines_and_strips_carriage_returns(self):
+        assert _sanitize_for_log("x\ny\rz") == "x yz"
+
+    def test_non_string_input_is_stringified(self):
+        assert _sanitize_for_log(42) == "42"
+
+
 class TestProxyBaseLLMRequestProcessing:
     @pytest.mark.asyncio
     async def test_common_processing_pre_call_logic_pre_call_hook_receives_litellm_call_id(