CVE-2020-37289

LOW 3.7

Vyper before 0.3.1 Improper Input Validation of uint8 Interface Return Values

CVSS Score

3.7

EPSS Score

0.0%

EPSS Percentile

0th

Vyper before 0.3.1 lacks a uint8 type, allowing interface return values declared as uint8, such as ERC20.decimals(), to be stored in uint256 variables without bounds checking. Malicious contracts can return values greater than 255 to manipulate or bypass contract logic that relies on these values.

CWE	CWE-20
Vendor	vyperlang
Product	vyper
Published	Oct 21, 2026

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CVSS v3 Breakdown

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

Attack Vector

Network

Attack Complexity

High

Privileges Required

None

User Interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

Low

Availability

None

Affected Versions

vyperlang / vyper

0 < 0.3.1

References

NVD ↗ CVE.org ↗ EPSS Data ↗

github.com: https://github.com/vyperlang/vyper/security/advisories/GHSA-mr6r-mvw4-736g vulncheck.com: https://www.vulncheck.com/advisories/vyper-before-0.3.1-improper-input-validation-of-uint8-interface-return-values

Credits

montyly