CVE-2023-37276

aiohttp v3.8.4 and earlier HTTP server parser vulnerability

• CVSS 7.5
• CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')
• Input Validation and Sanitization
• Remote

aiohttp is an asynchronous HTTP client/server framework for asyncio and Python. aiohttp v3.8.4 and earlier are bundled with llhttp v6.0.6. Vulnerable code is used by aiohttp for its HTTP request parser when available which is the default case when installing from a wheel. This vulnerability only affects users of aiohttp as an HTTP server (ie `aiohttp.Application`), you are not affected by this vulnerability if you are using aiohttp as an HTTP client library (ie `aiohttp.ClientSession`). Sending a crafted HTTP request will cause the server to misinterpret one of the HTTP header values leading to HTTP request smuggling. This issue has been addressed in version 3.8.5. Users are advised to upgrade. Users unable to upgrade can reinstall aiohttp using `AIOHTTP_NO_EXTENSIONS=1` as an environment variable to disable the llhttp HTTP request parser implementation. The pure Python implementation isn't vulnerable.

CVE

CVE-2023-37276

CWE

CWE-444 Inconsistent Interpretation of HTTP Requests ('HTTP Request/Response Smuggling')

CVSS base score

7.5

Published

2023-07-19

OWASP

A06 Vulnerable and Outdated Components

Orthogonal defect classification

Function

Code defect classification

Incorrect Functionality

Category

Input Validation and Sanitization

Subcategory

Insecure Parsing or Deserialization

Accessibility scope

Remote

Impact

Denial of Service (DoS)

Fixed by upgrading

Yes

Solution

Update aiohttp to version 3.8.5 or higher.

from aiohttp import web

async def handle(request):
    return web.Response(text="Hello, world")

app = web.Application()
app.router.add_get('/', handle)

if __name__ == '__main__':
    web.run_app(app, port=8080)

import os
from aiohttp import web

os.environ['AIOHTTP_NO_EXTENSIONS'] = '1'

async def handle(request):
    return web.Response(text="Hello, world")

app = web.Application()
app.router.add_get('/', handle)

if __name__ == '__main__':
    web.run_app(app, port=8080)

@misc{vaitp:cve202337276,
  title        = {{aiohttp v3.8.4 and earlier HTTP server parser vulnerability}},
  author       = {Bogaerts, Fr\'ed\'eric and Ivaki, Naghmeh and Fonseca, Jos\'e},
  year         = {2023},
  note         = {VAITP Python Vulnerability Dataset, entry CVE-2023-37276},
  howpublished = {\url{https://netpack.pt/vaitp/vulnerability/CVE-2023-37276/}}
}