miguelgrinberg python-socketio up to 5.16.3 Binary Message resource consumption

Summaryinfo

A vulnerability described as problematic has been identified in miguelgrinberg python-socketio up to 5.16.3. This affects an unknown function of the component Binary Message Handler. Such manipulation leads to resource consumption. This vulnerability is traded as CVE-2026-48804. The attack may be launched remotely. There is no exploit available.

Detailsinfo

A vulnerability was found in miguelgrinberg python-socketio up to 5.16.3. It has been rated as problematic. Affected by this issue is an unknown code block of the component Binary Message Handler. The manipulation with an unknown input leads to a resource consumption vulnerability. Using CWE to declare the problem leads to CWE-400. The product does not properly control the allocation and maintenance of a limited resource, thereby enabling an actor to influence the amount of resources consumed, eventually leading to the exhaustion of available resources. Impacted is availability. CVE summarizes:

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.

The advisory is shared for download at github.com. This vulnerability is handled as CVE-2026-48804 since 05/22/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1499.

Upgrading to version 5.16.4 eliminates this vulnerability.

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Productinfo

Type

• Programming Language Software

Vendor

• miguelgrinberg

Name

• python-socketio

Version

• 5.16.0
• 5.16.1
• 5.16.2
• 5.16.3

Website

• Product: https://github.com/miguelgrinberg/python-socketio/

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