From aa125ecf0edb9cd67656553d11d643aeb444ff9e Mon Sep 17 00:00:00 2001
From: Cyrus Leung <tlleungac@connect.ust.hk>
Date: Fri, 9 Jan 2026 04:07:03 +0800
Subject: [PATCH] [Frontend] Improve error message (#31987)

Signed-off-by: DarkLight1337 <tlleungac@connect.ust.hk>
---
 tests/entrypoints/test_utils.py       | 10 ++++++++++
 vllm/entrypoints/openai/api_server.py |  8 ++++----
 vllm/entrypoints/utils.py             |  6 ++++++
 3 files changed, 20 insertions(+), 4 deletions(-)
 create mode 100644 tests/entrypoints/test_utils.py

diff --git a/tests/entrypoints/test_utils.py b/tests/entrypoints/test_utils.py
new file mode 100644
index 00000000000..dc110184064
--- /dev/null
+++ b/tests/entrypoints/test_utils.py
@@ -0,0 +1,10 @@
+# SPDX-License-Identifier: Apache-2.0
+# SPDX-FileCopyrightText: Copyright contributors to the vLLM project
+from vllm.entrypoints.utils import sanitize_message
+
+
+def test_sanitize_message():
+    assert (
+        sanitize_message("<_io.BytesIO object at 0x7a95e299e750>")
+        == "<_io.BytesIO object>"
+    )
diff --git a/vllm/entrypoints/openai/api_server.py b/vllm/entrypoints/openai/api_server.py
index b489eca5f8b..6cf90cea941 100644
--- a/vllm/entrypoints/openai/api_server.py
+++ b/vllm/entrypoints/openai/api_server.py
@@ -88,8 +88,10 @@ from vllm.entrypoints.utils import (
     log_non_default_args,
     process_chat_template,
     process_lora_modules,
+    sanitize_message,
     with_cancellation,
 )
+from vllm.exceptions import VLLMValidationError
 from vllm.logger import init_logger
 from vllm.reasoning import ReasoningParserManager
 from vllm.tasks import POOLING_TASKS
@@ -902,7 +904,7 @@ def build_app(args: Namespace) -> FastAPI:
     async def http_exception_handler(_: Request, exc: HTTPException):
         err = ErrorResponse(
             error=ErrorInfo(
-                message=exc.detail,
+                message=sanitize_message(exc.detail),
                 type=HTTPStatus(exc.status_code).phrase,
                 code=exc.status_code,
             )
@@ -911,8 +913,6 @@ def build_app(args: Namespace) -> FastAPI:
 
     @app.exception_handler(RequestValidationError)
     async def validation_exception_handler(_: Request, exc: RequestValidationError):
-        from vllm.exceptions import VLLMValidationError
-
         param = None
         for error in exc.errors():
             if "ctx" in error and "error" in error["ctx"]:
@@ -931,7 +931,7 @@ def build_app(args: Namespace) -> FastAPI:
 
         err = ErrorResponse(
             error=ErrorInfo(
-                message=message,
+                message=sanitize_message(message),
                 type=HTTPStatus.BAD_REQUEST.phrase,
                 code=HTTPStatus.BAD_REQUEST,
                 param=param,
diff --git a/vllm/entrypoints/utils.py b/vllm/entrypoints/utils.py
index f4a633c69cb..6f3e7c55f5b 100644
--- a/vllm/entrypoints/utils.py
+++ b/vllm/entrypoints/utils.py
@@ -9,6 +9,7 @@ from argparse import Namespace
 from pathlib import Path
 from typing import Any
 
+import regex as re
 from fastapi import Request
 from fastapi.responses import JSONResponse, StreamingResponse
 from starlette.background import BackgroundTask, BackgroundTasks
@@ -317,3 +318,8 @@ async def process_chat_template(
                     model_config.model,
                 )
     return resolved_chat_template
+
+
+def sanitize_message(message: str) -> str:
+    # Avoid leaking memory address from object reprs
+    return re.sub(r" at 0x[0-9a-f]+>", ">", message)