Buffer overflow in Vyperlang Vyper
CVE-2021-48020
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.
Vulnerability class: Buffer Overflow
Published .
CVSS v3 metric
CVSS v3 base score 6.5 (Medium). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:L.
EPSS exploit prediction
No EPSS score from FIRST.org yet. New CVEs usually get one within a few days; no score means no signal yet, not low risk. How EPSS works.
Affected products
Weakness classification (CWE)
References
- github.com/vyperlang/vyper/security/advisories/GHSA-22wc-c9wj-6q2v (vendor-advisory)
- www.vulncheck.com/advisories/vyper-before-0.3.0-memory-corruption-via-internal-… (third-party-advisory)
Frequently asked questions
- What is CVE-2021-48020?
- CVE-2021-48020 is a medium-severity vulnerability in Vyperlang Vyper, classified under Out-of-bounds Write. CVSS score: 6.5/10. Published 2026-10-21.
- How severe is CVE-2021-48020?
- Medium severity. CVSS v3 base score is 6.5 out of 10.