CVE-2025-61765 is a medium-severity (CVSS 6.4) Deserialization of Untrusted Data vulnerability in python-socketio. A fix is available for python-socketio — see the affected versions and patch details below.
python-socketio vulnerable to arbitrary Python code execution (RCE) through malicious pickle deserialization in certain multi-server deployments
Exploitation Status
No confirmed exploitation observed yet
- A successful exploit gives an attacker total control of the affected component, not partial access.
- CISA’s own triage has not observed active exploitation or public proof-of-concept code for this CVE as of its last assessment.
Exploitation and automatability from CISA’s SSVC triage for CVE-2025-61765.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
CVE-2025-61765 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 378,567 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
python-socketioReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
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
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | python-socketio | ≥ 0.8.0&&< 5.14.0 | 5.14.0pip install --upgrade 'python-socketio==5.14.0' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for python-socketio, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update python-socketio to 5.14.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2025-61765 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2025-61765 can be triaged on real exposure rather than presence alone.
Tailored to CVE-2025-61765. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is CVE-2025-61765 in your dependencies?
O3 Security finds CVE-2025-61765 across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.