# CVE-2026-111750: AIOHTTP: Pure-Python parser request smuggling

> An attacker can smuggle HTTP requests in AIOHTTP when using the pure Python parser, bypassing intermediary security controls.

- **Severity:** Medium 6.3 (`CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:L/SA:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 19 Oct 2026
- **Updated:** 28 Oct 2026
- **Also known as:** AZL-110695, DEBIAN-CVE-2026-111750, ECHO-b67a-7679-1b63, GHSA-pqxq-w44r-73xw, MINI-33gh-gj3f-7hg6, MINI-vcfv-f876-3mjm, MINI-xp92-5vjj-wcmq, UBUNTU-CVE-2026-111750

## What is CVE-2026-111750?

CVE-2026-111750 is a medium-severity 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, the pure Python parser accepts ambiguous HTTP request framing. An unauthenticated attacker can consequently smuggle requests when an application uses AIOHTTP_NO_EXTENSIONS or otherwise runs without a standard wheel and an intermediary interprets the framing differently. This issue is fixed in version 3.14.4.

Weakness: CWE-444 (Inconsistent Interpretation of HTTP Requests)

## Which versions are affected by CVE-2026-111750?

2 open source packages ship an affected version, including aiohttp.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `aiohttp` | PyPI | All versions | 3.14.4 |
| `aiohttp` | PyPI | All versions | 3.14.4 |

## How do I fix CVE-2026-111750?

Upgrade aiohttp to 3.14.4 or later.

## Is CVE-2026-111750 being exploited?

There is no known exploitation of CVE-2026-111750 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-111750 and fix it if it is affected.

What it is: CVE-2026-111750 is a medium-severity 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.
Exploitation: There is no known exploitation of CVE-2026-111750 in the wild and no public exploit code.

Affected packages and fixed versions:
- aiohttp (PyPI): affected all versions; fixed in 3.14.4
- aiohttp (PyPI): affected all versions; fixed in 3.14.4

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-111750/ (Markdown: https://insights.sbomify.com/CVE-2026-111750/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-111750
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-111750
- OSV: https://osv.dev/vulnerability/CVE-2026-111750

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-111750/
Summaries are generated and may contain mistakes; the official description above is the record.