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GHSA-v4jc-pm6r-3vj8

CriticalCVSS 9.8 / 10
Published Jun 18, 2026·Last modified Jun 18, 2026
Affected Components(0)

No affected components available

Description

Summary

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

1. Install:
   pip install python-statemachine==3.1.2

2. Create an SCXML file containing:
   <data id="x" expr="__import__('pathlib').Path('marker.txt').write_text('pwned')"/>

3. Run:
   SCXMLProcessor.parse_scxml_file(DATA_EXPR_CHART)
   SCXMLProcessor.start()

4. During start(), <data expr> reaches _eval(), which calls eval().

5. 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.

Risk Scores
Base Score
9.8

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a high impact on the confidentiality of the information. There is a high impact on the integrity of the data. There is a high impact on the availability of the system.

Threat Intelligence
9.0

Active exploitation in the wild has been confirmed. Immediate patching or mitigation is required.

EPSS
1.17%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

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