Qiskit SDK is vulnerable to specific functions may recurse too deeply and overflow the available stack space, when encountering certain classical expressions.
Summary
| CVE | CVE-2026-4870 |
|---|---|
| State | PUBLISHED |
| Assigner | ibm |
| Source Priority | CVE Program / NVD first with legacy fallback |
| Published | 2026-06-12 21:16:23 UTC |
| Updated | 2026-06-15 14:16:36 UTC |
| Description | IBM Qiskit SDK 0.43.0 through 2.5.0 could allow an attacker to trigger a segmentation fault leading to a denial of service due to uncontrolled recursion in the parser. |
Risk And Classification
Primary CVSS: v3.1 7.5 HIGH from [email protected]
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS: 0.000400000 probability, percentile 0.124220000 (date 2026-06-14)
Problem Types: CWE-674 | CWE-674 CWE-674 Uncontrolled Recursion
| Version | Source | Type | Score | Severity | Vector |
|---|---|---|---|---|---|
| 3.1 | [email protected] | Secondary | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| 3.1 | CNA | CVSS | 7.5 | HIGH | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
CVSS v3.1 Breakdown
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Vendor Declared Affected Products
| Source | Vendor | Product | Version | Platforms |
|---|---|---|---|---|
| CNA | IBM | Qiskit SDK | affected 0.43.0 2.5.0 semver | Not specified |
References
| Reference | Source | Link | Tags |
|---|---|---|---|
| www.ibm.com/support/pages/node/7276123 | [email protected] | www.ibm.com | |
| CVE Program record | CVE.ORG | www.cve.org | canonical |
| NVD vulnerability detail | NVD | nvd.nist.gov | canonical, analysis |
Vendor Comments And Credit
Discovery Credit
CNA: This vulnerability was reported to IBM by Ali Sherif. (en)
Additional Advisory Data
Solutions
CNA: Remediation/Fixes guidance: The issue is addressed in Qiskit versions v1.4.6 and v2.4.2. These are patched to error with a Python-space RecursionError exception once the expression depth exceeds the Python recursion limit which can be queried with sys.getrecursionlimit(). This limit can be adjusted by calling sys.setrecursionlimit(). Future versions of Qiskit may remove this limit entirely with a non-recursive version of the OpenQASM 2 parser. Product(s)Version(s) number and/or range Remediation/Fix/Instructions<Qiskit SDK - qiskit.qasm2.loads() function>v1.4.6 and v2.4.2 Upgrade to the patched versions: qiskit v1.4.6 or qiskit v2.4.2. <Qiskit SDK - QuantumCircuit.from_qasm_str function>v1.4.6 and v2.4.2 Upgrade to the patched versions: qiskit v1.4.6 or qiskit v2.4.2. <Qiskit SDK - QuantumCircuit.from_qasm_str function>v1.4.6 and v2.4.2 Upgrade to the patched versions: qiskit v1.4.6 or qiskit v2.4.2.
Workarounds
CNA: Workarounds/Mitigation guidance: None