Description
Qiskit could allow a local attacker to cause a denial of service due to a stack overflow during deserialization of QPY payloads. A malicious QPY payload can trigger a segmentation fault, causing the application to crash when deserializing untrusted input.
Published: 2026-09-03
Score: 6.2 Medium
EPSS: < 1% Very Low
KEV: No
Impact: Denial of Service
Action: Upgrade Patch
AI Analysis

Impact

IBM Qiskit SDK processes QPY files in a way that permits a local attacker to trigger a stack overflow when deserializing malicious payloads. The result is a segmentation fault that causes the application to crash, effectively denying service. The vulnerability is identified by CWE-502.

Affected Systems

The vulnerability affects IBM Qiskit SDK, specifically versions 2.1.0 up to 2.5.1 inclusive. The patch is included in version 2.5.2 and later, which disables the recursive evaluation of the expression tree during deserialization.

Risk and Exploitability

The CVSS score of 6.2 indicates moderate severity, and the EPSS score is reported as < 1%, suggesting a low likelihood of exploitation. The vulnerability is listed as not in CISA’s KEV catalog. Based on the description, the attack vector is likely local: an attacker must supply a malicious QPY file to the application, a condition that can be mitigated by removing or restricting untrusted QPY input. No workaround is available, so a direct code update is required.

Generated by OpenCVE AI on September 4, 2026 at 22:55 UTC.

Remediation

Vendor Solution

Remediation/Fixes guidance: The issue is addressed in Qiskit versions v2.5.2. This version is patched to prevent the stack overflow by no longer evaluating the expression tree for ParameterExpression objects recursively. Product(s)Version(s) number and/or range Remediation/Fix/Instructions<Qiskit SDK - qiskit.qpy.load() function>v2.5.2 Upgrade to the patched versions: qiskit v2.5.2.

Vendor Workaround

Workarounds/Mitigation guidance: None

OpenCVE Recommended Actions

  • Upgrade IBM Qiskit SDK to version 2.5.2 or later.
  • If an immediate upgrade is not possible, restrict QPY file acceptance to a trusted source list only.
  • Avoid loading QPY files from untrusted input; implement input validation or a sandboxed environment for QPY processing.

Generated by OpenCVE AI on September 4, 2026 at 22:55 UTC.

Tracking

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Advisories

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History

Fri, 04 Sep 2026 20:30:00 +0000

Type Values Removed Values Added
Description IBM Qiskit SDK 2.1.0 through 2.5.1 could allow a local attacker to cause a denial of service due to improper handling of a specially crafted object during deserialization. A malicious QPY payload can trigger a segmentation fault, causing the application to crash when deserializing untrusted input. Qiskit could allow a local attacker to cause a denial of service due to a stack overflow during deserialization of QPY payloads. A malicious QPY payload can trigger a segmentation fault, causing the application to crash when deserializing untrusted input.

Fri, 04 Sep 2026 14:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

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

Thu, 03 Sep 2026 20:15:00 +0000

Type Values Removed Values Added
Description IBM Qiskit SDK 2.1.0 through 2.5.1 could allow a local attacker to cause a denial of service due to improper handling of a specially crafted object during deserialization. A malicious QPY payload can trigger a segmentation fault, causing the application to crash when deserializing untrusted input.
Title Qiskit SDK is vulnerable when deserializing QPY Files and may overflow the available stack space.
First Time appeared Ibm
Ibm qiskit Sdk
Weaknesses CWE-502
CPEs cpe:2.3:a:ibm:qiskit_sdk:2.1.0:*:*:*:*:*:*:*
cpe:2.3:a:ibm:qiskit_sdk:2.5.1:*:*:*:*:*:*:*
Vendors & Products Ibm
Ibm qiskit Sdk
References
Metrics cvssV3_1

{'score': 6.2, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H'}

Subscriptions

Ibm Qiskit Sdk
cve-icon MITRE

Status: PUBLISHED

Assigner: ibm

Published:

Updated: 2026-09-04T20:05:30.490Z

Reserved: 2026-08-13T19:40:18.000Z

Link: CVE-2026-19795

cve-icon Vulnrichment

Updated: 2026-09-04T13:26:20.465Z

cve-icon NVD

Status : Awaiting Analysis

Published: 2026-09-03T20:17:19.790

Modified: 2026-09-08T14:17:08.940

Link: CVE-2026-19795

cve-icon Redhat

No data.

cve-icon OpenCVE Enrichment

Updated: 2026-09-04T23:00:17Z

Weaknesses
  • CWE-502

    Deserialization of Untrusted Data