What is CVE-2021-41121?

CVE-2021-41121 is a high-severity vulnerability in Vyperlang Vyper, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 7.5/10. Published 2021-10-06.

How severe is CVE-2021-41121?

High severity. CVSS v3 base score is 7.5 out of 10.

Buffer overflow in Vyperlang Vyper

CVE-2021-41121

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.

Vulnerability class: Buffer Overflow

Published 2021-10-06 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.011 (64.4th percentile), scored 2026-10-20.

Low probability of exploitation in the next 30 days, but still tracked. 64th percentile — 64.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.011 · newest: 0.011 · change: 0.000

Affected products

Vyperlang Vyper — versions < 0.3.0

Weakness classification (CWE)

CWE-119 — Improper Restriction of Operations within the Bounds of a Memory Buffer

References

github.com/vyperlang/vyper/pull/2447 (Patch, Third Party Advisory)
github.com/vyperlang/vyper/security/advisories/GHSA-xv8x-pr4h-73jv (Third Party Advisory)

Frequently asked questions

What is CVE-2021-41121?: CVE-2021-41121 is a high-severity vulnerability in Vyperlang Vyper, classified under Improper Restriction of Operations within the Bounds of a Memory Buffer. CVSS score: 7.5/10. Published 2021-10-06.
How severe is CVE-2021-41121?: High severity. CVSS v3 base score is 7.5 out of 10.