Answer in brief
CVE-2020-37289 records a Medium severity (CVSS 6.3) vulnerability in Vyper before 0.3.1 Improper Input Validation of uint8 Interface Return Values. The current sources do not mark it as known exploited. The current feed maps vyperlang/vyper (generic). Check affected ranges and fixed versions before updating.
Analysis pending evidence review
HOL Guard separates source facts from reviewed analysis. See the methodology.
CVSS is 6.3. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.
Analysis status
Analysis pending evidence review
Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.
The current feed maps vyperlang/vyper (generic). Check affected ranges and fixed versions before updating.
| Package | Affected range | Fixed version |
|---|---|---|
| vyperlang/vypergeneric | >=0 <0.3.1 | 0.3.1 |
Published upstream
Oct 21, 2026
Evidence: source:cvelist:source_dates:source-dates:recordSource modified
Oct 21, 2026
Evidence: source:cvelist:source_dates:source-dates:recordFirst seen by HOL
Oct 21, 2026
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.
Quoted source text, attributed separately from HOL analysis.