CVE-2026-116500 PUBLISHED

Unbound Recursion in QPY deserialization can lead to denial of service

Assigner: ibm
Reserved: 26.10.2026 Published: 08.11.2026 Updated: 08.11.2026

IBM Qiskit SDK 2.4.0 through 2.6.1 could allow a local attacker to cause a denial of service due to unbound recursion during deserialization of untrusted QPY payloads.

Metrics

CVSS 3.1

CVSS Vector: CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
CVSS Score: 6.2

Attack Vector	Local	Scope	Unchanged
Attack Complexity	Low	Confidentiality Impact	None
Privileges Required	None	Integrity Impact	None
User Interaction	None	Availability Impact	High

CVSS 3.1

Product Status

Vendor	IBM
Product	Qiskit SDK
Versions	affected from 2.4.0 to 2.6.1 (incl.)

Workarounds

Workarounds/Mitigation guidance:

None

Solutions

Remediation/Fixes guidance:

The issue is addressed in Qiskit versions v2.6.2.

Product(s)Version(s) number and/or range Remediation/Fix/Instructions< Qiskit SDK https://github.com/qiskit/qiskit - qiskit.qpy.load() function>v2.6.2

Upgrade to the patched versions: qiskit v2.6.2.

Credits

The vulnerability was reported to IBM by Nathan Rebello. finder

References

https://www.ibm.com/support/pages/node/7295235

Problem Types

CWE-502 Deserialization of Untrusted Data CWE