CVE-2026-116501

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

publishedCWE-787

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.

Technical severity8.4 highCVSS 3.1 · CNA: ibm

Published2026-11-08Source updated 2026-11-08

Collected2026-11-082 attributed sources

Fixes and workarounds

Fix

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.

Source: CNA: ibm

Workaround

Workarounds/Mitigation guidance: None

Source: CNA: ibm

Fix

The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.

Source: CNA: ibm

Affected products and versions

Affected products, source version ranges and reporting authorities
Product	Versions	Authority
Qiskit SDK IBM	≥ 2.4.0; ≤ 2.6.1 (affected, semver)	CNA: ibm

Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.

CVSS assessments

CVSS scores, vectors and reporting authorities
Version / score	Vector	Authority
3.1 / 8.4 high	`CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`	CNA: ibm
3.1 / 8.4 high	`CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H`	NVD: [email protected]

Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

References

https://www.ibm.com/support/pages/node/7295237CNA: ibm · vendor-advisory, patch
https://www.ibm.com/support/pages/node/7295237[email protected]

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