Vulnerability · Published Oct 21, 2026 · Assigned by VulnCheck

CVE-2020-37287Vyper before 0.2.6 Call Stack Corruption via Complex Type Function Arguments

Medium 5.9

In plain English

A medium-severity security flaw in vyper from vyperlang. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 17% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.9Medium

Exploit odds (30 days)0.3%top 83.3% of all CVEs

Exploited in the wildNo reportsCISA SSVC: none

Attack toolingNoneno public tooling known

Official description

Vyper before 0.2.6 contains a call stack corruption vulnerability that causes incorrect function outputs when complex types with non-base members are passed as arguments. Contracts passing multi-dimensional arrays or structs to internal or external functions receive corrupted values because the compiler assumed each subtype size is 32.

Affected packages & fixed versions

Ecosystem	Package	Fixed in	Advisory
PyPI	vyper	0.2.6	GHSA-4v7v-gqf9-ww2g

Affected products (as reported)

Vendor	Product	Versions
vyperlang	vyper	0 – before 0.2.6

Weakness: CWE-131 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:N

References

GitHub Security Advisory (GHSA-4v7v-gqf9-ww2g) vendor-advisory
VulnCheck Advisory: Vyper before 0.2.6 Call Stack Corruption via Complex Type Function Arguments third-party-advisory