CVE-2021-48020

Medium

Description

Vyper from 0.1.0b4 before 0.3.0 contains a memory corruption vulnerability caused by an incorrect stack tip pointer when internal function calls are performed inside arrays. Contracts placing internal calls in nested array elements, external call arguments, struct literals, or raw_log topics can have memory corrupted, producing incorrect contract behavior.

SeverityMedium

CVSS6.5

Exploit probability—

Product

Vyper

PublishedOct 21, 2026

First seenOct 21, 2026

Weakness typeCWE-787Out-of-bounds write

How to fix

Update

vyper0.2.12 or later

Vendor advisories

github.com/vyperlang/vyper/security/advisories/GHSA-22wc-c9wj-6q2v

Affected products

Product	Affected versions	Fixed in
vyperPyPI	v < 0.2.12	0.2.12

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