# CVE-2026-69243: AIOHTTP request smuggling in WebSocket upgrade

Source: https://junglewise.ai/threats/cve-2026-69243-aiohttp-request-smuggling-in-websocket-upgrade  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-08-03. Updated: 2026-08-03  
License: CC BY 4.0 with a link back

CVE-2026-69243 · Severity: medium · CVSS 4 · Published 2026-08-03

AIOHTTP is a popular Python library used to build web servers and handle web requests. A vulnerability in how it handles WebSocket connections could allow an attacker to "smuggle" hidden requests past security filters. This could potentially allow unauthorized actions or bypass security controls on the server.

Technologies: [aiohttp (PyPI)](https://junglewise.ai/threats/technologies/aiohttp). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2026-69243 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-69243 being exploited in the wild.

**How severe is CVE-2026-69243?** Medium severity, with a CVSS score of 4, published 3 August 2026.

**Which products and versions are affected?** aiohttp (PyPI) <= 3.14.1, ECOSYSTEM:introduced=0,fixed=3.14.2.

**Is there a fix for CVE-2026-69243?** Yes. aiohttp (PyPI): upgrade to 3.14.2 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-69243 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-69243?** Check whether you run aiohttp (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- aiohttp (PyPI): upgrade to 3.14.2 or later

  ```sh
  pip install "aiohttp>=3.14.2"
  ```


## Technical details

AIOHTTP's server-side component contains a flaw in its HTTP parser related to the WebSocket upgrade procedure (CWE-444). An attacker can exploit an edge case during the handshake to smuggle a second HTTP request within what appears to be a single connection. This is a network-based attack with high complexity, as it requires specific timing or formatting to bypass the parser's logic. Successful exploitation could allow an attacker to bypass security proxies or perform unauthorized actions on the backend server. The issue is fixed in version 3.14.2.

## Affected products

- aio-libs aiohttp <= 3.14.1

## Identifiers

- CVE-2026-69243
- GHSA-mfx4-hv73-q22v
- PYSEC-2026-3546

## Timeline

- 2026-07-26: disclosed
- 2026-08-03: advisory
- 2026-08-03: patched: Version 3.14.2 released

## References

- [https://api.github.com/users/shivams0099](https://api.github.com/users/shivams0099)
- [https://github.com/shivams0099](https://github.com/shivams0099)
- [https://api.github.com/users/shivams0099/gists%7B/gist_id%7D](https://api.github.com/users/shivams0099/gists%7B/gist_id%7D)
- [https://api.github.com/users/shivams0099/repos](https://api.github.com/users/shivams0099/repos)
- [https://avatars.githubusercontent.com/u/40691890?v=4](https://avatars.githubusercontent.com/u/40691890?v=4)
- [https://api.github.com/users/shivams0099/events%7B/privacy%7D](https://api.github.com/users/shivams0099/events%7B/privacy%7D)

## Related threats

- [aiohttp HTTP request smuggling in pure Python parser](https://junglewise.ai/threats/cve-2026-111750-aiohttp-is-an-asynchronous-http-client-server-framework-for)
- [aiohttp host-only cookie scope bypass in subdomain handling](https://junglewise.ai/threats/cve-2026-111749-aiohttp-is-an-asynchronous-http-client-server-framework-for)
- [aiohttp Request scheme manipulation in absolute-form requests](https://junglewise.ai/threats/cve-2026-111748-aiohttp-is-an-asynchronous-http-client-server-framework-for)
- [AIOHTTP multipart request file descriptor exhaustion](https://junglewise.ai/threats/cve-2026-111066-aiohttp-is-an-asynchronous-http-client-server-framework-for)
- [aiohttp cookie Max-Age integer overflow causes connection pool exhaustion](https://junglewise.ai/threats/cve-2026-111065-aiohttp-is-an-asynchronous-http-client-server-framework-for)