# CVE-2026-25632: EPyT-Flow has unsafe JSON deserialization (__type__)

> Attackers can execute arbitrary OS commands by sending malicious JSON payloads to the EPyT-Flow REST API or loading crafted files.

- **Severity:** Critical 10.0 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 6 Feb 2026
- **Updated:** 6 Feb 2026
- **Also known as:** GHSA-74vm-8frp-7w68, PYSEC-2026-330

## What is CVE-2026-25632?

CVE-2026-25632 is a critical unsafe deserialization vulnerability in WaterFutures EPyT-Flow, published on 6 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

EPyT-Flow is a Python package designed for the easy generation of hydraulic and water quality scenario data of water distribution networks. Prior to 0.16.1, EPyT-Flow’s REST API parses attacker-controlled JSON request bodies using a custom deserializer (my_load_from_json) that supports a type field. When type is present, the deserializer dynamically imports an attacker-specified module/class and instantiates it with attacker-supplied arguments. This allows invoking dangerous classes such as subprocess.Popen, which can lead to OS command execution during JSON parsing. This also affects the loading of JSON files. This vulnerability is fixed in 0.16.1.

Weakness: CWE-502 (Deserialization of Untrusted Data)

## Which versions are affected by CVE-2026-25632?

3 open source packages ship an affected version, including epyt-flow. It affects 1 product.


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `epyt-flow` | PyPI | All versions | 0.16.1 |
| `epyt-flow` | PyPI | All versions | 0.16.1 |
| `epyt-flow` | PyPI | All versions | 0.16.1 |

Products: Waterfutures Epyt-Flow.

## How do I fix CVE-2026-25632?

Upgrade epyt-flow to 0.16.1 or later.

## Is CVE-2026-25632 being exploited?

There is no known exploitation of CVE-2026-25632 in the wild and no public exploit code.

Public exploit code:

- CVE-2026-25632 — Fix Unsafe JSON Deserialization Leading to Remote Code Execution (github_poc): https://github.com/lazarus0x1337/CVE-2026-25632

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-25632 and fix it if it is affected.

What it is: CVE-2026-25632 is a critical unsafe deserialization vulnerability in WaterFutures EPyT-Flow, published on 6 Feb 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-25632 in the wild and no public exploit code.

Affected packages and fixed versions:
- epyt-flow (PyPI): affected all versions; fixed in 0.16.1
- epyt-flow (PyPI): affected all versions; fixed in 0.16.1
- epyt-flow (PyPI): affected all versions; fixed in 0.16.1

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-2026-25632/ (Markdown: https://insights.sbomify.com/CVE-2026-25632/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-25632
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-25632
- OSV: https://osv.dev/vulnerability/CVE-2026-25632

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-25632/
Summaries are generated and may contain mistakes; the official description above is the record.