aiohttp vulnerable to Denial of Service when trying to parse malformed POST requests
Summary
An attacker can send a specially crafted POST (multipart/form-data) request. When the aiohttp server processes it, the server will enter an infinite loop and be unable to process any further requests.
Impact
An attacker can stop the application from serving requests after sending a single request.
For anyone needing to patch older versions of aiohttp, the minimum diff needed to resolve the issue is (located in _read_chunk_from_length()):
diff --git a/aiohttp/multipart.py b/aiohttp/multipart.py
index 227be605c..71fc2654a 100644
--- a/aiohttp/multipart.py
+++ b/aiohttp/multipart.py
@@ -338,6 +338,8 @@ class BodyPartReader:
assert self._length is not None, "Content-Length required for chunked read"
chunk_size = min(size, self._length - self._read_bytes)
chunk = await self._content.read(chunk_size)
+ if self._content.at_eof():
+ self._at_eof = True
return chunk
async def _read_chunk_from_stream(self, size: int) -> bytes:This does however introduce some very minor issues with handling form data. So, if possible, it would be recommended to also backport the changes in: https://github.com/aio-libs/aiohttp/commit/cebe526b9c34dc3a3da9140409db63014bc4cf19 https://github.com/aio-libs/aiohttp/commit/7eecdff163ccf029fbb1ddc9de4169d4aaeb6597 https://github.com/aio-libs/aiohttp/commit/f21c6f2ca512a026ce7f0f6c6311f62d6a638866
Software afectado
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| Plataforma | Paquete | Versiones vulnerables | Corregida en |
|---|---|---|---|
| Python (PyPI) | aiohttp | < 3.9.4 | 3.9.4 |
Referencias
- https://github.com/aio-libs/aiohttp/security/advisories/GHSA-5m98-qgg9-wh84
- https://nvd.nist.gov/vuln/detail/CVE-2024-30251
- https://github.com/aio-libs/aiohttp/commit/7eecdff163ccf029fbb1ddc9de4169d4aaeb6597
- https://github.com/aio-libs/aiohttp/commit/cebe526b9c34dc3a3da9140409db63014bc4cf19
- https://github.com/aio-libs/aiohttp/commit/f21c6f2ca512a026ce7f0f6c6311f62d6a638866
- https://github.com/aio-libs/aiohttp
- https://lists.debian.org/debian-lts-announce/2025/02/msg00002.html
- http://www.openwall.com/lists/oss-security/2024/05/02/4
- https://pypi.org/project/aiohttp
- https://github.com/advisories/GHSA-5m98-qgg9-wh84
- Vector CVSS
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H- Debilidad (CWE)
CWE-835- Plataforma
- Python (PyPI)
- Paquete
aiohttp- Publicada
- 03.05.2024
- Actualizado
- 11.10.2026 15:17
Fuentes y licencias
OSV / GitHub Advisory Database - PYSEC-2026-1098 - PyPA Advisory Database; CC BY 4.0
OSV / GitHub Advisory Database - GHSA-5m98-qgg9-wh84 - CC BY 4.0
Historial de vulnerabilidades: aiohttp
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
- 55
- Primera → última
- 02.2021 10.2026
- Sin corrección
- 0
- Explotada en ataques
- 0
Distribución por gravedad
- Alta 7
- Media 29
- Baja 19
Divulgaciones por año
- 2021: 1
- 2022: 0
- 2023: 6
- 2024: 7
- 2025: 1
- 2026: 40
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aiohttp vulnerable to Denial of Service when trying to parse malformed POST requests esta entrada
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