new file mode 100644
@@ -0,0 +1,65 @@
+From 70f4c611ec466b6a33f1bce57d5776fac964919f Mon Sep 17 00:00:00 2001
+From: "patchback[bot]" <45432694+patchback[bot]@users.noreply.github.com>
+Date: Tue, 10 Mar 2026 22:14:02 +0000
+Subject: [PATCH] [PR #12216/9cc4b917 backport][3.13] Check multipart max_size
+ during iteration (#12229)
+
+**This is a backport of PR #12216 as merged into master
+(9cc4b917c54833a22f65edae7963d16a6eeb1f54).**
+
+---------
+
+CVE: CVE-2026-34517
+Upstream-Status: Backport [https://github.com/aio-libs/aiohttp/commit/cbb774f38330563422ca0c413a71021d7b944145]
+
+Backport Changes:
+- Replaced BodyPartReader.decode_iter() with aiohttp 3.9.5's
+ synchronous decode() API. Form-data does not support content
+ compression, so this preserves upstream's single-decode behavior
+ after bounded chunk reads.
+
+Co-authored-by: Sam Bull <git@sambull.org>
+(cherry picked from commit cbb774f38330563422ca0c413a71021d7b944145)
+Signed-off-by: Darsh Kelaiya <dkelaiya@cisco.com>
+---
+ aiohttp/web_request.py | 19 +++++++++++++------
+ 1 file changed, 13 insertions(+), 6 deletions(-)
+
+diff --git a/aiohttp/web_request.py b/aiohttp/web_request.py
+index 2ec09565c..f9de59573 100644
+--- a/aiohttp/web_request.py
++++ b/aiohttp/web_request.py
+@@ -760,17 +760,24 @@ class BaseRequest(MutableMapping[str, Any], HeadersMixin):
+ out.add(field.name, ff)
+ else:
+ # deal with ordinary data
+- value = await field.read(decode=True)
++ raw_data = bytearray()
++ while chunk := await field.read_chunk():
++ size += len(chunk)
++ if 0 < max_size < size:
++ raise HTTPRequestEntityTooLarge(
++ max_size=max_size, actual_size=size
++ )
++ raw_data.extend(chunk)
++
++ # aiohttp 3.9.5 has synchronous BodyPartReader.decode()
++ # and form-data does not support content compression.
++ value = field.decode(raw_data)
++
+ if field_ct is None or field_ct.startswith("text/"):
+ charset = field.get_charset(default="utf-8")
+ out.add(field.name, value.decode(charset))
+ else:
+ out.add(field.name, value)
+- size += len(value)
+- if 0 < max_size < size:
+- raise HTTPRequestEntityTooLarge(
+- max_size=max_size, actual_size=size
+- )
+ else:
+ raise ValueError(
+ "To decode nested multipart you need " "to use custom reader",
+--
+2.35.6
+
@@ -23,6 +23,7 @@ SRC_URI += "file://CVE-2024-52304.patch \
file://CVE-2026-34518.patch \
file://CVE-2026-34519.patch \
file://CVE-2026-34516.patch \
+ file://CVE-2026-34517.patch \
"
CVE_STATUS[CVE-2026-34515] = "not-applicable-platform: Vulnerability only affects applications running on Windows"