# 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.

- **Severity:** High 8.8 (`CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** No
- **Published:** 25 Nov 2025
- **Updated:** 26 Nov 2025
- **Also known as:** GHSA-xv5p-fjw5-vrj6, PYSEC-2026-1399

## 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 (Deserialization of Untrusted Data)

## Which versions are affected by CVE-2025-62703?

3 open source packages ship an affected version, including fugue. It affects 1 product.


| Package | Ecosystem | 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: 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.

## Is CVE-2025-62703 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-62703 exists.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-62703 and fix it if it is affected.

What it is: 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.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-62703 exists.

Affected packages and fixed versions:
- fugue (PyPI): affected all versions up to 0.9.2; no fix listed
- fugue (PyPI): affected all versions up to 0.9.2; no fix listed
- fugue (PyPI): affected all versions up to 0.9.2; no fix listed

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-62703/ (Markdown: https://insights.sbomify.com/CVE-2025-62703/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-62703
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-62703
- OSV: https://osv.dev/vulnerability/CVE-2025-62703

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From sbomify Insights: https://insights.sbomify.com/CVE-2025-62703/
Summaries are generated and may contain mistakes; the official description above is the record.