Parser crash via uncontrolled classical-expression recursion
Published Jun 12, 2026 · Updated Jun 12, 2026
Uncontrolled recursion in IBM Qiskit SDK 0.43.0 through 2.5.0 allows remote attackers to crash a consuming process via OpenQASM 2 input. The qiskit.qasm2.load and loads parsers recurse through nested classical expressions until native stack exhaustion causes a segmentation fault. Exploitation requires an application to pass attacker-controlled OpenQASM 2 text to an affected parser entry point, and the consequence is limited to crashing that process.
Summary
What happened
Uncontrolled recursion in IBM Qiskit SDK 0.43.0 through 2.5.0 allows remote attackers to crash a consuming process via OpenQASM 2 input. The qiskit.qasm2.load and loads parsers recurse through nested classical expressions until native stack exhaustion causes a segmentation fault. Exploitation requires an application to pass attacker-controlled OpenQASM 2 text to an affected parser entry point, and the consequence is limited to crashing that process.
The record
- CVE
- CVE-2026-4870
- Published
- Jun 12, 2026
- Updated
- Jun 12, 2026
- Vendor
- OpenBMC Project
- Product
- Qiskit
- Classifications
- CWE-674, T1499.004
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 12, 2026CVE publishedPublication date reported by the CVE source.
- Jun 12, 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?
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- Affected versionversion=0.43.0 <=2.5.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Public exploit references
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Technologies
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Your stack
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