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CVE-2026-48804GHSA-5W7Q-77MV-V69FPYSEC-2026-3042

python-socketio: Binary attachment accumulation can cause denial of service

Published
Last modified
published
Not listed in CISA KEV
Fix
Fixed in 5.16.4, 5.16.2
None on Exploit-DB, Metasploit or GitHub
  • Exploitation: none
  • Automatable: yes
  • Technical impact: partial

Summary

python-socketio is a Python implementation of the Socket.IO realtime client and server. The python-socketio server stores binary `EVENT` and `ACK` messages in memory while it waits to receive their binary attachments. Once all the attachments are received, these messages are then processed. Prior to version 5.16.4, an attacker can submit a binary message and intentionally omit sending one or more of its attachments to cause the message along with the partial list of received attachments to stay in memory for a long time. Version 5.16.4 takes the following measures to address this issue: Binary packets are only accepted from authenticated clients and, when a client disconnects, the server checks if there is a partial binary message being held for the client and deletes it.

Timeline

  1. CVE published
  2. CISA SSVC assessment

    Exploitation: none · Automatable: yes · Technical impact: partial

  3. Record last updated

Affected versions

  • miguelgrinberg python-socketio

    fixed in 5.16.4

  • python-socketioPyPI

    fixed in 5.16.2

References 2

GitHub · miguelgrinberg/python-socketio