Process crash via recursive ParameterExpression evaluation
Published Sep 3, 2026 · Updated Sep 4, 2026
Stack overflow in Qiskit SDK 2.1.0 through 2.5.1 allows local users to crash a process by loading a crafted QPY payload. The qiskit.qpy.load() path recursively evaluates attacker-controlled ParameterExpression trees until the native stack is exhausted and the interpreter segfaults. The payload must reach a local process that deserializes untrusted QPY data; the consequence is a process crash without reported data access or modification.
Summary
What happened
Stack overflow in Qiskit SDK 2.1.0 through 2.5.1 allows local users to crash a process by loading a crafted QPY payload. The qiskit.qpy.load() path recursively evaluates attacker-controlled ParameterExpression trees until the native stack is exhausted and the interpreter segfaults. The payload must reach a local process that deserializes untrusted QPY data; the consequence is a process crash without reported data access or modification.
The record
- CVE
- CVE-2026-19795
- Published
- Sep 3, 2026
- Updated
- Sep 4, 2026
- Vendor
- IBM
- Product
- Qiskit SDK
- Classifications
- CWE-502, T1499.004
- Attack vector
- local
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 3, 2026CVE publishedPublication date reported by the CVE source.
- Sep 4, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=2.1.0 <=2.5.1
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What is affected?
Published CVSS scores
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Attacks
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Public exploit references
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Technologies
Your stack
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Your stack
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