diff --git a/backend/pyproject.toml b/backend/pyproject.toml
index 11d1065b3..8023fd42e 100644
--- a/backend/pyproject.toml
+++ b/backend/pyproject.toml
@@ -8,7 +8,7 @@ dependencies = [
     "deerflow-harness",
     "fastapi>=0.115.0",
     "httpx>=0.28.0",
-    "python-multipart>=0.0.20",
+    "python-multipart>=0.0.26",
     "sse-starlette>=2.1.0",
     "uvicorn[standard]>=0.34.0",
     "lark-oapi>=1.4.0",
diff --git a/backend/uv.lock b/backend/uv.lock
index 609e8336d..af739264b 100644
--- a/backend/uv.lock
+++ b/backend/uv.lock
@@ -698,7 +698,7 @@ requires-dist = [
     { name = "langgraph-sdk", specifier = ">=0.1.51" },
     { name = "lark-oapi", specifier = ">=1.4.0" },
     { name = "markdown-to-mrkdwn", specifier = ">=0.3.1" },
-    { name = "python-multipart", specifier = ">=0.0.20" },
+    { name = "python-multipart", specifier = ">=0.0.26" },
     { name = "python-telegram-bot", specifier = ">=21.0" },
     { name = "slack-sdk", specifier = ">=3.33.0" },
     { name = "sse-starlette", specifier = ">=2.1.0" },
@@ -3135,11 +3135,11 @@ wheels = [
 
 [[package]]
 name = "python-multipart"
-version = "0.0.22"
+version = "0.0.26"
 source = { registry = "https://pypi.org/simple" }
-sdist = { url = "https://files.pythonhosted.org/packages/94/01/979e98d542a70714b0cb2b6728ed0b7c46792b695e3eaec3e20711271ca3/python_multipart-0.0.22.tar.gz", hash = "sha256:7340bef99a7e0032613f56dc36027b959fd3b30a787ed62d310e951f7c3a3a58", size = 37612, upload-time = "2026-01-25T10:15:56.219Z" }
+sdist = { url = "https://files.pythonhosted.org/packages/88/71/b145a380824a960ebd60e1014256dbb7d2253f2316ff2d73dfd8928ec2c3/python_multipart-0.0.26.tar.gz", hash = "sha256:08fadc45918cd615e26846437f50c5d6d23304da32c341f289a617127b081f17", size = 43501, upload-time = "2026-04-10T14:09:59.473Z" }
 wheels = [
-    { url = "https://files.pythonhosted.org/packages/1b/d0/397f9626e711ff749a95d96b7af99b9c566a9bb5129b8e4c10fc4d100304/python_multipart-0.0.22-py3-none-any.whl", hash = "sha256:2b2cd894c83d21bf49d702499531c7bafd057d730c201782048f7945d82de155", size = 24579, upload-time = "2026-01-25T10:15:54.811Z" },
+    { url = "https://files.pythonhosted.org/packages/9a/22/f1925cdda983ab66fc8ec6ec8014b959262747e58bdca26a4e3d1da29d56/python_multipart-0.0.26-py3-none-any.whl", hash = "sha256:c0b169f8c4484c13b0dcf2ef0ec3a4adb255c4b7d18d8e420477d2b1dd03f185", size = 28847, upload-time = "2026-04-10T14:09:58.131Z" },
 ]
 
 [[package]]