highCVSS 7.5Vulnerability

CVE-2026-48809

### 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.

Properties

ghsa_id
GHSA-m9gh-vj53-gvh9
severity
high
summary
python-engineio has possible denial of service due to maximum payload size sometimes not being enforced
cvss_score
7.5
cve_id
CVE-2026-48809
cvss_vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
is_ghsa_only
false
ghsa_published
2026-06-26T20:48:18Z
source_url
https://github.com/advisories/GHSA-m9gh-vj53-gvh9
ghsa_updated
2026-06-26T20:48:19Z

Related Entities (4)

VULNERABLE_TO (1)

[Software]pip/python-engineio

AFFECTS (1)

[Software]pip/python-engineio

HAS_WEAKNESS (1)

[Weakness]Allocation of Resources Without Limits or Throttling

REPORTED_BY (1)

[Source]GitHub Advisory Database

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CVE-2026-48809 (CVSS 7.5) — Ninja Signal Threat Intelligence | Ninja Signal