PYSEC-2026-506
Vulnerability from pysec - Published: 2026-06-29 11:50 - Updated: 2026-06-29 12:05Summary
python-statemachine 3.1.2 evaluates <data expr="..."> attributes in SCXML documents using Python's eval(). Any application that passes attacker-controlled SCXML content to SCXMLProcessor is vulnerable to arbitrary code execution in the context of the hosting process.
Details
SCXMLProcessor.parse_scxml_file() processes SCXML documents and evaluates <data> element expr attributes via the following call chain:
SCXMLProcessor.parse_scxml_file()
SCXMLProcessor.process_definition()
create_datamodel_action_callable()
_create_dataitem_callable()
_eval()
eval()
```
`_eval()` calls Python's built-in `eval()` directly on the expression string without sandboxing or restriction.
### PoC
-
Install: pip install python-statemachine==3.1.2
-
Create an SCXML file containing:
-
Run: SCXMLProcessor.parse_scxml_file(DATA_EXPR_CHART) SCXMLProcessor.start()
-
During start(), reaches _eval(), which calls eval().
-
Result: data_marker_before_start: False data_marker_after_start: True success: True ```
Impact
This is an eval injection vulnerability (CWE-95). Remote or local code execution depending on whether the consuming application accepts SCXML content from remote users, uploaded files, configuration, plugins, or other untrusted sources.
| Name | purl | python-statemachine |
|---|
{
"affected": [
{
"package": {
"ecosystem": "PyPI",
"name": "python-statemachine"
},
"ranges": [
{
"events": [
{
"introduced": "3.0.0"
},
{
"fixed": "3.2.0"
}
],
"type": "ECOSYSTEM"
}
],
"versions": [
"3.0.0",
"3.1.0",
"3.1.1",
"3.1.2"
]
}
],
"aliases": [
"CVE-2026-47103",
"GHSA-v4jc-pm6r-3vj8"
],
"details": "### Summary\n\npython-statemachine 3.1.2 evaluates `\u003cdata expr=\"...\"\u003e` attributes in SCXML documents using Python\u0027s `eval()`. Any application that passes attacker-controlled SCXML content to `SCXMLProcessor` is vulnerable to arbitrary code execution in the context of the hosting process.\n\n### Details\n\n`SCXMLProcessor.parse_scxml_file()` processes SCXML documents and evaluates `\u003cdata\u003e` element `expr` attributes via the following call chain:\n\n```\nSCXMLProcessor.parse_scxml_file()\nSCXMLProcessor.process_definition()\n create_datamodel_action_callable()\n_create_dataitem_callable()\n_eval()\neval()\n ```\n\n`_eval()` calls Python\u0027s built-in `eval()` directly on the expression string without sandboxing or restriction.\n\n### PoC\n\n```\n1. Install:\n pip install python-statemachine==3.1.2\n\n2. Create an SCXML file containing:\n \u003cdata id=\"x\" expr=\"__import__(\u0027pathlib\u0027).Path(\u0027marker.txt\u0027).write_text(\u0027pwned\u0027)\"/\u003e\n\n 3. Run:\n SCXMLProcessor.parse_scxml_file(DATA_EXPR_CHART)\n SCXMLProcessor.start()\n \n4. During start(), \u003cdata expr\u003e reaches _eval(), which calls eval().\n\n5. Result:\n data_marker_before_start: False\n data_marker_after_start: True\n success: True\n```\n\n### Impact\n\nThis is an eval injection vulnerability (CWE-95). Remote or local code execution depending on whether the consuming application accepts SCXML content from remote users, uploaded files, configuration, plugins, or other untrusted sources.",
"id": "PYSEC-2026-506",
"modified": "2026-06-29T12:05:45.826276Z",
"published": "2026-06-29T11:50:52.079977Z",
"references": [
{
"type": "WEB",
"url": "https://github.com/fgmacedo/python-statemachine/security/advisories/GHSA-v4jc-pm6r-3vj8"
},
{
"type": "ADVISORY",
"url": "https://nvd.nist.gov/vuln/detail/CVE-2026-47103"
},
{
"type": "PACKAGE",
"url": "https://github.com/fgmacedo/python-statemachine"
},
{
"type": "WEB",
"url": "https://github.com/fgmacedo/python-statemachine/releases/tag/v3.2.0"
},
{
"type": "WEB",
"url": "https://www.vulncheck.com/advisories/python-statemachine-rce-via-scxml-eval-injection"
},
{
"type": "PACKAGE",
"url": "https://pypi.org/project/python-statemachine"
},
{
"type": "ADVISORY",
"url": "https://github.com/advisories/GHSA-v4jc-pm6r-3vj8"
}
],
"severity": [
{
"score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"type": "CVSS_V3"
},
{
"score": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"type": "CVSS_V4"
}
],
"summary": "python-statemachine SCXML \u003cdata expr\u003e Eval Injection"
}
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.