{"api_version":"1","generated_at":"2026-06-15T18:21:25+00:00","cve":"CVE-2026-4870","urls":{"html":"https://cve.report/CVE-2026-4870","api":"https://cve.report/api/cve/CVE-2026-4870.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-4870","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-4870"},"summary":{"title":"Qiskit SDK is vulnerable to specific functions may recurse too deeply and overflow the available stack space, when encountering certain classical expressions.","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.","state":"PUBLISHED","assigner":"ibm","published_at":"2026-06-12 21:16:23","updated_at":"2026-06-15 14:16:36"},"problem_types":["CWE-674","CWE-674 CWE-674 Uncontrolled Recursion"],"metrics":[{"version":"3.1","source":"psirt@us.ibm.com","type":"Secondary","score":"7.5","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"CVSS","score":"7.5","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","data":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"}}],"references":[{"url":"https://www.ibm.com/support/pages/node/7276123","name":"https://www.ibm.com/support/pages/node/7276123","refsource":"psirt@us.ibm.com","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-4870","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-4870","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"IBM","product":"Qiskit SDK","version":"affected 0.43.0 2.5.0 semver","platforms":[]}],"timeline":[],"solutions":[{"source":"CNA","title":"","value":"Remediation/Fixes guidance:\n\n\n\nThe 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.\n\n\n\n\n\nProduct(s)Version(s) number and/or range Remediation/Fix/Instructionsv1.4.6 and v2.4.2\n\nUpgrade to the patched versions: qiskit v1.4.6 or qiskit v2.4.2.\n\nv1.4.6 and v2.4.2\n\nUpgrade to the patched versions: qiskit v1.4.6 or qiskit v2.4.2.\n\nv1.4.6 and v2.4.2\n\nUpgrade to the patched versions: qiskit v1.4.6 or qiskit v2.4.2.","time":"","lang":"en"}],"workarounds":[{"source":"CNA","title":"","value":"Workarounds/Mitigation guidance:\n\n\n\n\nNone","time":"","lang":"en"}],"exploits":[],"credits":[{"source":"CNA","value":"This vulnerability was reported to IBM by Ali Sherif.","lang":"en"}],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"4870","cve":"CVE-2026-4870","epss":"0.000400000","percentile":"0.124220000","score_date":"2026-06-14","updated_at":"2026-06-15 00:14:08"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"adp":[{"metrics":[{"other":{"content":{"id":"CVE-2026-4870","options":[{"Exploitation":"none"},{"Automatable":"yes"},{"Technical Impact":"partial"}],"role":"CISA Coordinator","timestamp":"2026-06-15T13:37:33.434370Z","version":"2.0.3"},"type":"ssvc"}}],"problemTypes":[{"descriptions":[{"cweId":"CWE-674","description":"CWE-674 Uncontrolled Recursion","lang":"en","type":"CWE"}]}],"providerMetadata":{"dateUpdated":"2026-06-15T13:37:47.830Z","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP"},"title":"CISA ADP Vulnrichment"}],"cna":{"affected":[{"cpes":["cpe:2.3:a:ibm:qiskit_sdk:0.43.0:*:*:*:*:*:*:*","cpe:2.3:a:ibm:qiskit_sdk:2.5.0:*:*:*:*:*:*:*"],"product":"Qiskit SDK","vendor":"IBM","versions":[{"lessThanOrEqual":"2.5.0","status":"affected","version":"0.43.0","versionType":"semver"}]}],"credits":[{"lang":"en","type":"finder","value":"This vulnerability was reported to IBM by Ali Sherif."}],"descriptions":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"

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.

"}],"value":"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."}],"metrics":[{"cvssV3_1":{"attackComplexity":"LOW","attackVector":"NETWORK","availabilityImpact":"HIGH","baseScore":7.5,"baseSeverity":"HIGH","confidentialityImpact":"NONE","integrityImpact":"NONE","privilegesRequired":"NONE","scope":"UNCHANGED","userInteraction":"NONE","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"format":"CVSS","scenarios":[{"lang":"en","value":"GENERAL"}]}],"providerMetadata":{"dateUpdated":"2026-06-12T20:52:58.528Z","orgId":"9a959283-ebb5-44b6-b705-dcc2bbced522","shortName":"ibm"},"references":[{"tags":["vendor-advisory","patch"],"url":"https://www.ibm.com/support/pages/node/7276123"}],"solutions":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"

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.

"}],"value":"Remediation/Fixes guidance:\n\n\n\nThe 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.\n\n\n\n\n\nProduct(s)Version(s) number and/or range Remediation/Fix/Instructionsv1.4.6 and v2.4.2\n\nUpgrade to the patched versions: qiskit v1.4.6 or qiskit v2.4.2.\n\nv1.4.6 and v2.4.2\n\nUpgrade to the patched versions: qiskit v1.4.6 or qiskit v2.4.2.\n\nv1.4.6 and v2.4.2\n\nUpgrade to the patched versions: qiskit v1.4.6 or qiskit v2.4.2."}],"title":"Qiskit SDK is vulnerable to specific functions may recurse too deeply and overflow the available stack space, when encountering certain classical expressions.","workarounds":[{"lang":"en","supportingMedia":[{"base64":false,"type":"text/html","value":"

Workarounds/Mitigation guidance:


None

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