python-engineio has possible denial of service due to maximum payload size sometimes not being enforced
Impact
There are two specific configurations of the python-engineio server in which the size of incoming messages is not checked before the messages are loaded into memory. An attacker can take advantage of these to cause unnecessary memory allocations in the python-engineio server. The two cases are:
- POST requests, when using ASGI with the long polling transport
- WebSocket messages, when using Aiohttp with the WebSocket transport
Patches
Version 4.13.2 addresses this issue as follows:
- ASGI severs now only load the body of incoming requests into memory after the client is confirmed to be known and authenticated, and the payload size is below the maximum allowed size. Requests that do not comply with these requirements are discarded.
- Aiohttp servers configure the maximum payload size in the underlying WebSocket layer from Aiohttp, so that large messages are discarded by Aiohttp before they are delivered to python-engineio.
Software afectado
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| Plataforma | Paquete | Versiones vulnerables | Corregida en |
|---|---|---|---|
| Python (PyPI) | python-engineio | < 4.13.2 | 4.13.2 |
Referencias
- Vector CVSS
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- Debilidad (CWE)
CWE-770- Plataforma
- Python (PyPI)
- Paquete
python-engineio- Publicada
- 26.06.2026
- Actualizado
- 11.10.2026 14:18
Fuentes y licencias
OSV / GitHub Advisory Database - PYSEC-2026-3033 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-m9gh-vj53-gvh9 - CC BY 4.0
Historial de vulnerabilidades: python-engineio
Todas las vulnerabilidades publicadas de este paquete (Python (PyPI)), de la más reciente a la más antigua. Muestra si es un fallo aislado o un paquete que hay que vigilar.
- Entradas en total
- 3
- Primera → última
- 07.2019 06.2026
- Sin corrección
- 0
- Explotada en ataques
- 0
Distribución por gravedad
- Alta 3
Divulgaciones por año
- 2019: 1
- 2020: 0
- 2021: 0
- 2022: 0
- 2023: 0
- 2024: 0
- 2025: 0
- 2026: 2
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python-engineio has possible denial of service due to maximum payload size sometimes not being enforced esta entrada
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