---
id: CVE-2026-50269
aliases:
  - GHSA-m6qw-4cw2-hm4m
  - PYSEC-2026-2106
title: 'aiohttp: CRLF injection in multipart headers'
summary: 'aiohttp: CRLF injection in multipart headers'
severity: low
vendor: aiohttp
product: aiohttp
ecosystem: pip
affected:
  - aiohttp < 3.14.0
patched:
  - aiohttp 3.14.0
published: '2026-06-15'
updated: '2026-09-10'
sourceUpdated: '2026-09-10T03:51:09.078868018Z'
source: OSV
sourceUrl: 'https://osv.dev/vulnerability/GHSA-m6qw-4cw2-hm4m'
references:
  - url: >-
      https://github.com/aio-libs/aiohttp/security/advisories/GHSA-m6qw-4cw2-hm4m
  - url: >-
      https://github.com/aio-libs/aiohttp/commit/bf88077ebb14f4c29924b8e8904cba20c55c28b8
  - url: 'https://github.com/aio-libs/aiohttp'
  - url: 'https://github.com/advisories/GHSA-m6qw-4cw2-hm4m'
tags:
  - osv
  - pip
  - ghsa
epss: 0.00533
epssPercentile: 0.42619
cwe:
  - CWE-93
  - CWE-113
ingestedAt: '2026-07-07T15:41:58.696Z'
---

## Overview

### Summary

Attacker-controlled input included into multipart/payload headers can be used to modify a request to inject additional headers or similar.

### Impact

In the unlikely situation that an application is passing user-controlled strings into `MultipartWriter.append(headers=...)` or `Payload.headers`, then an attacker may be able to modify the request to inject headers or change the contents of the request.

### Workaround

Sanitise such user input.

-----

Patch: https://github.com/aio-libs/aiohttp/commit/bf88077ebb14f4c29924b8e8904cba20c55c28b8

## Affected packages

- `aiohttp < 3.14.0`

## Remediation

Upgrade to a patched release:

- `aiohttp 3.14.0`