Vulnerability record/PUBLISHED/Published Oct 21, 2026 00:36:17 UTC

CVE-2020-37289

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.

Base score6.3/ 10

SeverityMediumCVSS 4.0

Exploitability / impact

CVSS metric breakdown

Vector-derived attributes

Base severityMedium

Attack vectorNetworkAV

Attack complexityLowAC

Attack requirementsPresentAT

Privileges requiredNonePR

User interactionNoneUI

Vulnerable system confidentialityNoneVC

Vulnerable system integrityLowVI

Vulnerable system availabilityNoneVA

Subsequent system confidentialityNoneSC

Subsequent system integrityNoneSI

Subsequent system availabilityNoneSA

CVSS vector stringCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

CVSS communicates standardized severity and impact characteristics. It does not establish whether a system is exploitable in your specific environment.

Record context

CVE Numbering AuthorityVulnCheck

Last updatedOct 28, 2026 15:45:18 UTC

PublishedOct 21, 2026 00:36:17 UTC

ReservedOct 20, 2026 21:53:41 UTC

Credits

montyly