CVE-2026-111064 aiohttp server lacks an initial request/header timeout
Attackers can exhaust server connection capacity by keeping idle connections open indefinitely due to missing initial request timeout handling.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-111064?
CVE-2026-111064 is a high-severity denial of service vulnerability in aio-libs aiohttp, published on 19 Oct 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
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.
Weakness: CWE-770
Which versions are affected by CVE-2026-111064?
2 open source packages ship an affected version, including aiohttp.
| Package | Affected | Fixed in |
|---|---|---|
aiohttp PyPI | All versions | 3.14.4 |
aiohttp PyPI | All versions | 3.14.4 |
How do I fix CVE-2026-111064?
Upgrade aiohttp to 3.14.4 or later.
Upgrade, then put limits on request size, rate and nesting depth so one client cannot exhaust the service. More about Denial of service.
Is CVE-2026-111064 being exploited?
There is no known exploitation of CVE-2026-111064 in the wild and no public exploit code.
Sources
Also known as AZL-109887, DEBIAN-CVE-2026-111064, ECHO-2d22-25db-f131, GHSA-5wr8-gcqf-gqf3, MINI-gqf2-9wpr-47rv, MINI-hq2w-7825-cr8m and 3 more.