AIOHTTP has a Multipart Header Size Bypass

高 7.5CVE-2026-34516 · GHSA-m5qp-6w8w-w647 · PYSEC-2026-2098 · 01/04/2026 公開 · 26/10/2026 更新

要点

CVE-2026-34516 は aiohttp, aiohttp (aiohttp) に影響する深刻度「高」 (CVSS 7.5) の脆弱性です。
今後30日間に悪用される確率（EPSS）：0.46%（全脆弱性の 39.7% より高い）。
対処：3.13.4 以降に更新してください。

パッケージ	影響を受けるバージョン	修正済みバージョン
aiohttp PyPI	`< 3.13.4`	`3.13.4`
aiohttp aiohttp	`< 3.13.4`	`3.13.4`

概要

Summary

A response with an excessive number of multipart headers may be allowed to use more memory than intended, potentially allowing a DoS vulnerability.

Impact

Multipart headers were not subject to the same size restrictions in place for normal headers, potentially allowing substantially more data to be loaded into memory than intended. However, other restrictions in place limit the impact of this vulnerability.

Patch: https://github.com/aio-libs/aiohttp/commit/8a74257b3804c9aac0bf644af93070f68f6c5a6f

NVD の説明

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to version 3.13.4, a response with an excessive number of multipart headers may be allowed to use more memory than intended, potentially allowing a DoS vulnerability. This issue has been patched in version 3.13.4.