CVE-2026-4870
Qiskit SDK is vulnerable to specific functions may recurse too deeply and overflow the available stack space, when encountering certain classical expressions.
02 Description
Qiskit SDK is vulnerable to specific functions may recurse too deeply and overflow the available stack space, when encountering certain classical expressions.
03 Exploitation and scoring
- Exploitation
- Assessed, none found. CISA's assessment recorded neither public exploit code nor evidence of exploitation when it was made.
- SSVC decision
- ExploitationnoneCISA recorded no public exploit code and no evidence of exploitation.
- AutomatableyesAn attacker can reliably automate reconnaissance through exploitation, so this scales.
- Technical ImpactpartialSuccessful exploitation gives limited control of the vulnerable component.
- EPSS probability
- 0.26% probability of exploitation activity in the next 30 days.
- EPSS percentile
- Equal to or higher than the score of 18.7% of scored records. A rank, not a probability.
- NVD base score
- 7.5 (CVSS v3.x), scored by the NVD independently of the CNA.
- NVD CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- NVD analysis status
- Analyzed. NVD last modified this record on 2026-10-25.
- Red Hat severity
- No Red Hat rating. Red Hat rates the CVEs that affect its products.
Exploit-prediction scores from FIRST. Independent scoring and analysis status from the NVD. Vendor severity from Red Hat. Exploitation assessment and catalog membership from CISA.
04 Metadata
- Published
- 2026-06-12 20:52Z4 MO AGO
- Last updated
- 2026-06-15 13:37Z4 MO AGO
- Reserved
- 2026-03-25
- Assigning CNA
- ibm
- Record state
- PUBLISHED
- Severity
- High (CVSS 7.5)
- CNA CVSS vector
- CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- Weaknesses
- CWE-674Uncontrolled RecursionClass
- Data version
- 5.2
- Document digest
- b0b79a8fa8dbaaee3f4f2325a411755389cb5522023d088f84fa7aeebf5d7a00
05 Affected products
06 References
07 Remediation
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.