CVE-2025-61765: 
Python vulnerability analysis and mitigation

A remote code execution vulnerability (CVE-2025-61765) was discovered in python-socketio versions prior to 5.14.0. The vulnerability affects multi-server deployments where attackers can execute arbitrary Python code through malicious pickle deserialization if they gain access to the message queue used for internal server communications. The vulnerability was disclosed on October 3, 2025, affecting versions >= 0.8.0 and < 5.14.0 (GitHub Advisory).

The vulnerability stems from the use of Python's pickle module for encoding messages between servers in multi-server deployments using message queue backends like Redis. When a server receives messages through the message queue, it assumes the message is trusted and immediately deserializes it using Python's pickle.loads() function. An attacker with access to the message queue can craft a malicious pickle payload that executes arbitrary code during deserialization via Python's reduce method. The vulnerability has been assigned a CVSS v3.1 score of 6.4 (Medium) with vector string CVSS:3.1/AV:A/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:L and is classified as CWE-502 (Deserialization of Untrusted Data) (GitHub Advisory).

The vulnerability only affects deployments with a compromised message queue. If exploited, attackers can execute arbitrary 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 properly secured message queues are not vulnerable to this attack (GitHub Advisory).

Users should upgrade to python-socketio version 5.14.0 or newer, which removes the pickle module and replaces it with safer JSON encoding for inter-server messaging. Additionally, standard security practices should be followed in the deployment of the message queue to prevent unauthorized access (GitHub Advisory).