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.
EPyT-Flow has been patched in 0.16.1 -- affects all versions <= 0.16.0
Do not load any JSON from untrusted sources and do not expose the REST API.
EPyT-Flow thanks Jarrett Chan (@syphonetic) for detecting and reporting the bug.
0.16.1Exploitability
AV:NAC:LPR:NUI:NScope
S:CImpact
C:HI:HA:H10.0/CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:H/I:H/A:H