CVE-2025-61765python-socketio vulnerable to arbitrary Python code execution (RCE) through malicious pickle deserialization in certain multi-server deployments

Official description

python-socketio is a Python implementation of the Socket.IO realtime client and server. A remote code execution vulnerability in python-socketio versions prior to 5.14.0 allows attackers to execute arbitrary Python code through malicious pickle deserialization in multi-server deployments on which the attacker previously gained access to the message queue that the servers use for internal communications. When Socket.IO servers are configured to use a message queue backend such as Redis for inter-server communication, messages sent between the servers are encoded using the `pickle` Python module. When a server receives one of these messages through the message queue, it assumes it is trusted and immediately deserializes it. The vulnerability stems from deserialization of messages using Python's `pickle.loads()` function. Having previously obtained access to the message queue, the attacker can send a python-socketio server a crafted pickle payload that executes arbitrary code during deserialization via Python's `__reduce__` method. This vulnerability only affects deployments with a compromised message queue. The attack can lead to the attacker executing random code in the context of, and with the privileges of a Socket.IO server process. Single-server systems that do not use a message queue, and multi-server systems with a secure message queue are not vulnerable. In addition to making sure standard security practices are followed in the deployment of the message queue, users of the python-socketio package can upgrade to version 5.14.0 or newer, which remove the `pickle` module and use the much safer JSON encoding for inter-server messaging.

Affected packages & fixed versions

Affected products (as reported)

References

• https://github.com/miguelgrinberg/python-socketio/security/advisories/GHSA-g8c6-8fjj-2r4m x_refsource_CONFIRM
• https://github.com/miguelgrinberg/python-socketio/commit/53f6be094257ed81476b0e212c8cddd6d06ca39a x_refsource_MISC
• https://www.bluerock.io/post/cve-2025-61765-bluerock-discovers-critical-rce-in-socket-io-ecosystem x_refsource_MISC