# CVE-2026-54274: aio-libs aiohttp memory exhaustion in WebSocket handler

Source: https://junglewise.ai/threats/cve-2026-54274-aio-libs-aiohttp-memory-exhaustion-in-websocket-handler  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-06-22. Updated: 2026-06-22  
License: CC BY 4.0 with a link back

CVE-2026-54274 · Severity: medium · CVSS 4 · Published 2026-06-22

AIOHTTP is a popular Python library used to build web servers and clients. A vulnerability in how it handles WebSocket connections allows an attacker to bypass memory safety limits by sending incomplete data packets. This can lead to a denial-of-service (DoS) condition where the server crashes or becomes unresponsive due to excessive memory consumption.

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

## Quick answers

**Is CVE-2026-54274 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-54274 being exploited in the wild.

**How severe is CVE-2026-54274?** Medium severity, with a CVSS score of 4, published 22 June 2026.

**Which products and versions are affected?** aiohttp (PyPI) <= 3.14.0, ECOSYSTEM:introduced=0,fixed=3.14.1.

**Is there a fix for CVE-2026-54274?** Yes. aiohttp (PyPI): upgrade to 3.14.1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-54274 attacked?** It is attacked over the network, in a software library.

**Am I affected by CVE-2026-54274?** 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 3.14.1 or later

  ```sh
  pip install "aiohttp>=3.14.1"
  ```


## Technical details

A resource exhaustion vulnerability (CWE-770) exists in AIOHTTP's WebSocket implementation. The root cause is a failure to strictly enforce memory usage limits when processing large, incomplete WebSocket frame payloads. An unauthenticated remote attacker can exploit this by initiating a WebSocket connection and sending specially crafted incomplete frames, causing the server to allocate memory beyond configured thresholds. This can lead to a Denial of Service (DoS) via memory exhaustion. The issue is resolved in version 3.14.1 by improving WebSocket frame validation and check mechanisms.

## Affected products

- aio-libs aiohttp < 3.14.1

## Identifiers

- CVE-2026-54274
- GHSA-xcgm-r5h9-7989
- PYSEC-2026-2108

## Timeline

- 2026-06-08: advisory: GitHub Security Advisory published
- 2026-06-22: disclosed: NVD publication date
- 2026-06-22: patched: Fix released in version 3.14.1

## References

- [https://github.com/aio-libs/aiohttp/commit/14b6ee851fb16ec199acb950de0c82d476799e7d](https://github.com/aio-libs/aiohttp/commit/14b6ee851fb16ec199acb950de0c82d476799e7d)
- [https://github.com/aio-libs/aiohttp/security/advisories/GHSA-xcgm-r5h9-7989](https://github.com/aio-libs/aiohttp/security/advisories/GHSA-xcgm-r5h9-7989)

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