---
title: "CVE-2026-25632: EPyT-Flow vulnerable to unsafe JSON deserialization (__type__)"
url: https://erroneo.us/security/cve/CVE-2026-25632/
description: "CVE-2026-25632 (epyt-flow (PyPI)): EPyT-Flow is a Python package designed for the easy generation of hydraulic and water quality scenario data of water…"
type: vulnerability-record
section: "Security Digest"
date_published: 2026-02-06
date_modified: 2026-02-06
publisher: erroneo.us
author: erroneo.us Security Desk
cve: "CVE-2026-25632"
kev: false
cvss: 10
epss: 0.01423
license: All rights reserved. Quote with attribution and a link.
---

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

**Signal:** Critical and remotely reachable. No known exploitation yet, but it is network-reachable without credentials. (Computed from CISA KEV, EPSS and CVSS; not an editorial verdict.)

## Should you act?

- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 1.4% , percentile 73: FIRST’s model estimates a 1.4% chance of exploitation activity in the next 30 days, higher than 73% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
- Remotely reachable with no login and no user interaction. If the vulnerable service is exposed to the internet, prioritize it.
- Only applies if your dependency tree includes epyt-flow (PyPI) < 0.16.1, fixed in 0.16.1 . Check your lockfile, including transitive dependencies.

## What it is

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 (myloadfromjson) 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.

## Affected packages

- PyPI `epyt-flow` < 0.16.1 → fixed: 0.16.1

## Affected products (CVE record)

- WaterFutures EPyT-Flow: < 0.16.1

## Severity

- GitHub_M CVSS 3.1: 10 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H`
- GitHub CVSS 3.1: 10.0 `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H`

## Exploitation

- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none , automatable yes , technical impact total .
- FIRST EPSS (model of 2026-10-21): 1.42% probability of exploitation activity in the next 30 days; percentile 73.

## Sources

- [GitHub Advisory GHSA-74vm-8frp-7w68](https://github.com/advisories/GHSA-74vm-8frp-7w68)
- [CVE.org record CVE-2026-25632](https://www.cve.org/CVERecord?id=CVE-2026-25632)
- [NVD entry CVE-2026-25632](https://nvd.nist.gov/vuln/detail/CVE-2026-25632)
- [github.com](https://github.com/WaterFutures/EPyT-Flow/security/advisories/GHSA-74vm-8frp-7w68)
- [github.com](https://github.com/WaterFutures/EPyT-Flow/commit/3fff9151494c7dbc72073830b734f0a7e550e385)
- [github.com](https://github.com/WaterFutures/EPyT-Flow/releases/tag/v0.16.1)

---
Source page: https://erroneo.us/security/cve/CVE-2026-25632/ · Security Digest: https://erroneo.us/security/ · More: https://erroneo.us/llms.txt