# AIOHTTP has problems in HTTP parser (the python one, not llhttp)

Advisory record · `GHSA-gfw2-4jvh-wgfg`

- **Identifiers:** `GHSA-gfw2-4jvh-wgfg` · `CVE-2023-47627` · `PYSEC-2023-246`
- **State:** Confirmed
- **Severity:** CVSS 5.3 Medium
- **Critical:** No
- **Weakness (CWE):** [CWE-444](https://cwe.mitre.org/data/definitions/444.html)
- **Tags:** [HTTP request smuggling](https://agentprime.io/advisories/tag/request-smuggling.md)
- **Published:** 14 Nov 2023
- **Updated:** 10 Sept 2026
- **Reviewed by a person:** No

Published by the GitHub Advisory Database at 14 Nov 2023, 22:20 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

## Affected packages

- `aiohttp` (PyPI): affected `<3.8.6`; fixed in `3.8.6`

## Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

> The pure-Python HTTP parser in aiohttp, used only when AIOHTTP_NO_EXTENSIONS is set or the prebuilt llhttp-based parser is not used, is affected in versions before 3.8.6. It mishandles Content-Length values, NUL, CR and LF characters in header values, and whitespace before colons in header names, which can enable request smuggling by a remote client sending crafted requests. Upgrade to aiohttp 3.8.6 or later.

Written 5 Nov 2026.

## Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

## Severity and exploitation

- 5.3 Medium, CVSS 3.1: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N`, from CNA (GitHub_M)

- **CISA KEV:** Not listed.
- **EPSS:** 0.0086, the 58th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

## Timeline

- 31 Oct 2026, 14:36 UTC: First seen by agentprime
- 31 Oct 2026, 14:36 UTC: [Confirmed by OSV](https://osv.dev/vulnerability/GHSA-gfw2-4jvh-wgfg)

## Sources

- [GitHub Advisory Database: GHSA-gfw2-4jvh-wgfg](https://github.com/advisories/GHSA-gfw2-4jvh-wgfg)
- [OSV: GHSA-gfw2-4jvh-wgfg](https://osv.dev/vulnerability/GHSA-gfw2-4jvh-wgfg)
- <https://github.com/aio-libs/aiohttp/security/advisories/GHSA-gfw2-4jvh-wgfg>
- <https://nvd.nist.gov/vuln/detail/CVE-2023-47627>
- <https://github.com/aio-libs/aiohttp/commit/d5c12ba890557a575c313bb3017910d7616fce3d>
- <https://github.com/aio-libs/aiohttp>
- <https://github.com/aio-libs/aiohttp/releases/tag/v3.8.6>
- <https://github.com/pypa/advisory-database/tree/main/vulns/aiohttp/PYSEC-2023-246.yaml>
- <https://lists.debian.org/debian-lts-announce/2025/02/msg00002.html>
- <https://lists.fedoraproject.org/archives/list/package-announce@lists.fedoraproject.org/message/FUSJVQ7OQ55RWL4XAX2F5EZ73N4ZSH6U>
- <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>

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.

## Check whether this affects you

A Match means an installed version is in the affected range above. Most don’t affect the app; agentprime hasn’t analysed this one yet.

- With the agentprime MCP server (<https://api.agentprime.io/mcp>), ask your agent to check the project: `check_lockfile` sends a lockfile, `check_packages` a list of installed packages, and both return the Matches and the upgrades that clear them. `get_advisory` returns this record. Setup: <https://agentprime.io/mcp.md>
- In a browser: <https://agentprime.io/check/> reads your lockfile in the browser, never uploading it.
- Whether it touches your code, with file and line: the Claude Code plugin, <https://agentprime.io/plugin.md>
- As JSON: <https://api.agentprime.io/v1/advisories/GHSA-gfw2-4jvh-wgfg>, or `POST https://api.agentprime.io/v1/match` with your packages (<https://agentprime.io/api.md>)

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The web page: <https://agentprime.io/advisories/GHSA-gfw2-4jvh-wgfg/>. Everything for agents: <https://agentprime.io/llms.txt>.