CVE-2025-62703 Fugue is Vulnerable to Remote Code Execution by Pickle Deserialization via FlaskRPCServer
Attackers can execute arbitrary code on Fugue RPC servers by sending malicious pickle data, requiring immediate patching for users of this distributed computing library.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Local or same network only
- Victim action needed
- Not needed
- Fix
- None listed
What is CVE-2025-62703?
CVE-2025-62703 is a high-severity unsafe deserialization vulnerability in fugue-project fugue, published on 25 Nov 2025. It can only be exploited from the same machine or local network, with no action from the victim.
Official description
Fugue is a unified interface for distributed computing that lets users execute Python, Pandas, and SQL code on Spark, Dask, and Ray with minimal rewrites. In version 0.9.2 and prior, there is a remote code execution vulnerability by pickle deserialization via FlaskRPCServer. The Fugue framework implements an RPC server system for distributed computing operations. In the core functionality of the RPC server implementation, I found that the _decode() function in fugue/rpc/flask.py directly uses cloudpickle.loads() to deserialize data without any sanitization. This creates a remote code execution vulnerability when malicious pickle data is processed by the RPC server. The vulnerability exists in the RPC communication mechanism where the client can send arbitrary serialized Python objects that will be deserialized on the server side, allowing attackers to execute arbitrary code on the victim's machine. This issue has been patched via commit 6f25326.
Weakness: CWE-502
Which versions are affected by CVE-2025-62703?
3 open source packages ship an affected version, including fugue. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
fugue PyPI | All versions to 0.9.2 | None |
fugue PyPI | All versions to 0.9.2 | None |
fugue PyPI | All versions to 0.9.2 | None |
Products include Fugue-Project Fugue.
How do I fix CVE-2025-62703?
No fix has been published for CVE-2025-62703 yet. Limit exposure of the affected software until one is available.
Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.
Is CVE-2025-62703 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-62703 exists.
Sources
Also known as GHSA-xv5p-fjw5-vrj6, PYSEC-2026-1399.