CVE-2026-111066 AIOHTTP: File descriptor exhaustion in multipart requests
An unauthenticated attacker can exhaust file descriptors via crafted multipart requests, causing denial of service in applications using aiohttp.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2026-111066?
CVE-2026-111066 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. From 2.0.0 until 3.14.4, multipart request processing can retain an unbounded number of open file descriptors. An unauthenticated attacker can consequently exhaust file descriptors with specially crafted multipart requests when a handler uses Request.post(). This issue is fixed in version 3.14.4.
Which versions are affected by CVE-2026-111066?
2 open source packages ship an affected version, including aiohttp.
| Package | Affected | Fixed in |
|---|---|---|
aiohttp PyPI | From 2.0.0 | 3.14.4 |
aiohttp PyPI | From 2.0.0 | 3.14.4 |
How do I fix CVE-2026-111066?
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-2026-111066 being exploited?
There is no known exploitation of CVE-2026-111066 in the wild and no public exploit code.
Sources
Also known as AZL-109881, CLSA-2026-1792636819, CLSA-2026-1792740383, CLSA-2026-1792740391, CLSA-2026-1792742634, DEBIAN-CVE-2026-111066 and 7 more.