CVE-2026-116501

Qiskit SDK C API may trigger an out of bounds write on accessing the unitary matrix with qk_circuit_inst_unitary().

Published Nov 8, 2026 CVSS 3.1 · 8.4 High EPSS < 1% KEV · Not listed
Description
IBM Qiskit SDK 2.4.0 through 2.6.1 could allow a local attacker to execute arbitrary code due to an out-of-bounds write caused by improper input validation when accessing a corrupted unitary matrix.

Remediation

Vendor Solution

Remediation/Fixes guidance: The issue is addressed in Qiskit versions v2.6.2. This version is patched to detect this situation and write out a sentinel value to identify the instruction is in an inconsistent state. Product(s)Version(s) number and/or range Remediation/Fix/Instructions< Qiskit SDK https://github.com/qiskit/qiskit - qk_circuit_inst_unitary() function>v2.6.2 Upgrade to the patched versions: qiskit v2.6.2.


Vendor Workaround

Workarounds/Mitigation guidance: None

Tracking

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Advisories

No advisories available
History
Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'no', 'Exploitation': 'none', 'Technical Impact': 'total'}, 'version': '2.0.3'}

Type Values Removed Values Added
Description IBM Qiskit SDK 2.4.0 through 2.6.1 could allow a local attacker to execute arbitrary code due to an out-of-bounds write caused by improper input validation when accessing a corrupted unitary matrix.
Title Qiskit SDK C API may trigger an out of bounds write on accessing the unitary matrix with qk_circuit_inst_unitary().
First Time appeared Ibm
Ibm qiskit Sdk
Weaknesses CWE-787
CPEs cpe:2.3:a:ibm:qiskit_sdk:2.4.0:*:*:*:*:*:*:*
cpe:2.3:a:ibm:qiskit_sdk:2.6.1:*:*:*:*:*:*:*
Vendors & Products Ibm
Ibm qiskit Sdk
References
Metrics cvssV3_1

{'score': 8.4, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H'}

Weaknesses

Sources

Status
PUBLISHED
Assigner
ibm
Published
Updated
Nov 10, 2026, 4:56 AM
Reserved
Oct 26, 2026, 1:00 PM
Status
Awaiting Analysis
Published
Nov 8, 2026, 5:16 PM
Modified
Nov 10, 2026, 5:17 AM