Contract misexecution via repeated iterator evaluation
Published Feb 21, 2025 · Updated Feb 22, 2025
Incorrect code generation in Vyper before 0.4.1 allows attackers to cause smart contracts to execute unintended loop behavior. The compiler instantiates a complex fixed-array iterator inside repeat IR, reevaluating conditional iterator reads after loop-body storage writes instead of caching the list once. Exposure requires affected source code to use such an iterator and the resulting contract path to execute; consequences depend on that contract's logic.
Summary
What happened
Incorrect code generation in Vyper before 0.4.1 allows attackers to cause smart contracts to execute unintended loop behavior. The compiler instantiates a complex fixed-array iterator inside repeat IR, reevaluating conditional iterator reads after loop-body storage writes instead of caching the list once. Exposure requires affected source code to use such an iterator and the resulting contract path to execute; consequences depend on that contract's logic.
The record
- CVE
- CVE-2025-27104
- Published
- Feb 21, 2025
- Updated
- Feb 22, 2025
- Vendor
- Vyper
- Product
- Vyper
- Classifications
- CWE-662
- Attack vector
- Unavailable
- Privileges
- Unavailable
Timeline
How it unfolded
- Feb 21, 2025CVE publishedPublication date reported by the CVE source.
- Feb 22, 2025Record 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=< 0.4.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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