EPyT-Flow vulnerable to unsafe JSON deserialization (__type__)

CVE-2026-25632 → View on GitHub ↗ View on CVE.org ↗ View on NVD ↗

Description

Impact

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.

Patches

EPyT-Flow has been patched in 0.16.1 -- affects all versions <= 0.16.0

Workarounds

Do not load any JSON from untrusted sources and do not expose the REST API.

Credits

EPyT-Flow thanks Jarrett Chan (@syphonetic) for detecting and reporting the bug.

Basic information

Type
reviewed
Severity
critical
Advisory on GitHub
Open advisory ↗
Repository advisory
Open repository advisory ↗
Source code
Browse source ↗
Published (advisory)
2026-02-04 20:34:28 UTC
Updated
2026-02-06 21:43:50 UTC
GitHub reviewed
2026-02-04 20:34:28 UTC
NVD published
2026-02-06

EPSS Score

Score Percentile
0.08% 24.13%

CVSS Scores

Base score Version Severity Vector
10.0 3.1 —
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:C)
Breaking this can reach past the original component and bite other resources—bigger blast radius.
Confidentiality (C:H)
Serious risk that confidential data gets exposed in a big way.
Integrity (I:H)
They could widely tamper with or forge data—trust in the data is badly hurt.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.

Identifiers

Type Value
GHSA GHSA-74vm-8frp-7w68 ↗
CVE CVE-2026-25632 ↗

CWEs

CWE id Name
CWE-502 Deserialization of Untrusted Data

Credits

  • syphonetic (reporter)

Affected packages (1)

Vulnerable version ranges and first patched releases as published by GitHub.

Ecosystem Package Vulnerable range First patched Vulnerable functions
pip epyt-flow < 0.16.1 0.16.1 —

References

cvelogic Threat Intelligence