Smart-contract logic manipulation via incomplete bytestring comparison
Published Apr 4, 2022 · Updated Apr 23, 2025
Incorrect bytestring comparison in Vyper 0.3.1 and earlier allows remote attackers to alter smart-contract logic via crafted inputs. Equality code generation for Bytes and String values of at most 32 bytes compares a full word without checking lengths or masking unused bytes. A deployed contract must apply the affected comparison to attacker-controlled values; false equality can redirect contract decisions and state changes.
Summary
What happened
Incorrect bytestring comparison in Vyper 0.3.1 and earlier allows remote attackers to alter smart-contract logic via crafted inputs. Equality code generation for Bytes and String values of at most 32 bytes compares a full word without checking lengths or masking unused bytes. A deployed contract must apply the affected comparison to attacker-controlled values; false equality can redirect contract decisions and state changes.
The record
- CVE
- CVE-2022-24787
- Published
- Apr 4, 2022
- Updated
- Apr 23, 2025
- Vendor
- Vyper
- Product
- Vyper
- Classifications
- CWE-697
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Apr 4, 2022CVE publishedPublication date reported by the CVE source.
- Apr 23, 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?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=<= 0.3.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Upstream bytestring equality demonstrationproof of concept · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
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Your stack
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