CVE-2021-41121: Memory corruption in Vyper

Severity: high (CVSS 8.8 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 1.1% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2021-10-06 · updated 2026-06-17
Weakness: CWE-119

Description

Vyper is a Pythonic Smart Contract Language for the EVM. In affected versions when performing a function call inside a literal struct, there is a memory corruption issue that occurs because of an incorrect pointer to the the top of the stack. This issue has been resolved in version 0.3.0.

Affected products

vyperlang vyper: before 0.3.0 — fixed in 0.3.0

How to fix

Upgrade to a fixed version: vyperlang vyper 0.3.0. Check the vendor advisory for mitigations.

References

https://github.com/vyperlang/vyper/pull/2447
https://github.com/vyperlang/vyper/security/advisories/GHSA-xv8x-pr4h-73jv
https://github.com/vyperlang/vyper/pull/2447
https://github.com/vyperlang/vyper/security/advisories/GHSA-xv8x-pr4h-73jv

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