GHSA-v4jc-pm6r-3vj8 — python-statemachine
CRITICALGHSA-v4jc-pm6r-3vj8 is a critical-severity (CVSS 9.8) CWE-95 vulnerability in python-statemachine. A fix is available for python-statemachine — see the affected versions and patch details below.
python-statemachine SCXML <data expr> Eval Injection
Exploitation Status
Proof-of-concept exploit code exists
- CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.
- CISA assesses this as automatable — exploitation doesn’t require manual, per-target effort, which raises the odds of mass scanning and opportunistic attacks.
- A successful exploit gives an attacker total control of the affected component, not partial access.
Exploitation and automatability from CISA’s SSVC triage for GHSA-v4jc-pm6r-3vj8.
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
GHSA-v4jc-pm6r-3vj8 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 379,842 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
python-statemachineReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects PyPI packages — download data is not available via public APIs for these ecosystems.
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.
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | python-statemachine | ≥ 3.0.0&&< 3.2.0 | 3.2.0pip install --upgrade 'python-statemachine==3.2.0' |
Affected Products
python statemachinefgmacedoDetection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for python-statemachine, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update python-statemachine to 3.2.0 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-v4jc-pm6r-3vj8 is resolved across your whole dependency graph.
Workarounds
Stop passing untrusted input into the interpreter or shell: call the affected binary with an argument array rather than a composed command string, reject anything outside a strict allowlist of expected values, and run the component under an account that cannot reach beyond the work it legitimately does.
Frequently Asked Questions
Is GHSA-v4jc-pm6r-3vj8 in your dependencies?
Find it across PyPI, including transitive dependencies.