SB2026052522 - Multiple vulnerabilities in Python Engine.IO

Description

This security bulletin contains information about 2 vulnerabilities.

1) Allocation of Resources Without Limits or Throttling (CVE-ID: N/A)

CWE-ID: CWE-770 - Allocation of Resources Without Limits or Throttling

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to allocation of resources without limits or throttling in the python-engineio server when handling POST requests with ASGI long polling or WebSocket messages with Aiohttp WebSocket transport. A remote attacker can send oversized messages to cause a denial of service.

The issue occurs only in two specific server configurations: ASGI with the long polling transport, and Aiohttp with the WebSocket transport.

2) Allocation of Resources Without Limits or Throttling (CVE-ID: N/A)

CWE-ID: CWE-770 - Allocation of Resources Without Limits or Throttling

CVSSv4: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green

The vulnerability allows a remote attacker to cause a denial of service.

The vulnerability exists due to allocation of resources without limits or throttling in the heartbeat mechanism when handling new connections and PONG packets. A remote attacker can send connection attempts and crafted PONG packets to cause a denial of service.

This issue primarily affects synchronous servers, while asynchronous servers allocate background tasks instead of physical threads.

Remediation

Install update from vendor's website.

References

• https://github.com/miguelgrinberg/python-engineio/security/advisories/GHSA-m9gh-vj53-gvh9
• https://github.com/miguelgrinberg/python-engineio/security/advisories/GHSA-cgwc-pv48-fhj5