Allocation of Resources Without Limits or Throttling Affecting python-engineio package, versions *


Severity

Recommended
low

Based on default assessment until relevant scores are available.

Threat Intelligence

EPSS
0.58% (46th percentile)

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  • Snyk IDSNYK-DEBIAN11-PYTHONENGINEIO-18860659
  • published16 Aug 2026
  • disclosed11 Aug 2026

Introduced: 11 Aug 2026

CVE-2026-48802  (opens in a new tab)
CWE-770  (opens in a new tab)

How to fix?

There is no fixed version for Debian:11 python-engineio.

NVD Description

Note: Versions mentioned in the description apply only to the upstream python-engineio package and not the python-engineio package as distributed by Debian. See How to fix? for Debian:11 relevant fixed versions and status.

python-engineio is a Python implementation of the Engine.IO realtime client and server. Prior to version 4.13.2, an attacker can cause the creation of unnecessary background threads in the python-engineio server by exploiting the heartbeat mechanism, which launches a thread when a new connection is received, and when the client sends a PONG packet. This issue primarily affects synchronous servers. Asynchronous servers allocate background tasks instead of physical threads, which are lightweight and less likely to cause denial of service. However, the fix that was implemented was also applied to the asynchronous case. Version 4.13.2 addresses this issue as follows: The initial background thread (or async task( for heartbeat management is only launched if a client passes authentication in the connect handler; and the server now ensures that there is only one background heatbeat thread (or async task) per client at a given point in time. Out of sequence PONG packets are now discarded when an active heartbeat thread is already running.

CVSS Base Scores

version 3.1