---
id: "CVE-2026-111064"
kind: "vulnerability"
aliases: ["CVE-2026-111064", "GHSA-5wr8-gcqf-gqf3"]
title: "aiohttp server lacks an initial request/header timeout"
severity: "high"
cvss: 8.2
epss: 0.0039900001138448715
exploited: false
status: "open"
category: "package"
products: [{"name": "aiohttp", "fixed": ["3.14.4"], "affected": "<= 3.14.3", "ecosystem": "pypi"}]
ecosystems: ["pypi"]
tags: ["aiohttp", "cwe-770", "package", "python", "self-hosted"]
not_affected_if: ["behind-reverse-proxy-with-timeouts", "version-3.14.4-or-later"]
published_at: "2026-10-19T17:08:04+00:00"
first_seen_at: "2026-10-23T19:11:32+00:00"
updated_at: "2026-10-23T21:57:18+00:00"
sources: [{"source": "ghsa", "url": "https://github.com/advisories/GHSA-5wr8-gcqf-gqf3", "first_seen_at": "2026-10-23T19:11:32+00:00"}, {"source": "nvd", "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-111064", "first_seen_at": "2026-10-23T21:57:18+00:00"}]
---

# aiohttp server lacks an initial request/header timeout

aiohttp's server did not apply its keepalive timeout to the start of a new request, so a client could hold an idle connection open indefinitely without sending data. An attacker can tie up server connections and exhaust resources by opening many such connections.

_Summary, check and fix written by a model from the sources; labelled as such._

## Affected

- pypi:aiohttp affected <= 3.14.3 fixed 3.14.4

## How to check

pip show aiohttp (or check the lockfile) and look for a version at or below 3.14.3
Source says the server is affected when running aiohttp directly, which is the default for an aiohttp web app without a reverse proxy in front

## Fix

Upgrade aiohttp to 3.14.4 or later.
Until upgraded, put a reverse proxy with sensible keepalive and header timeouts in front of the app.

## Timeline

- 2026-10-23T19:11:32+00:00 ghsa https://github.com/advisories/GHSA-5wr8-gcqf-gqf3
- 2026-10-23T21:57:18+00:00 nvd https://nvd.nist.gov/vuln/detail/CVE-2026-111064

## From the sources

AIOHTTP is an asynchronous HTTP client/server framework for asyncio and Python. Prior to 3.14.4, keepalive timeout handling is absent during the initial portion of a request. An attacker can keep an idle connection open indefinitely before sending any request data, consuming server connection capacity. This issue is fixed in version 3.14.4.

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_Free to read at a human pace. An API with keys and an MCP server are in preparation; early access: hello@infrastack.ai_