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.

CVSS 4.0

8.3CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:N/SA:N

CVSS 3.1

6.5CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:H/A:L

EPSS

0.3% chance of exploitation in the next 30 days; higher than 20% of CVEs (scores of 2026-10-25)

CWE

CWE-787

Published

2026-10-21

Modified

2026-10-22

Record from

the NVD, synced 2026-10-23

Packages (OSV)

References

• https://github.com/vyperlang/vyper/security/advisories/GHSA-22wc-c9wj-6q2v
• https://www.vulncheck.com/advisories/vyper-before-0.3.0-memory-corruption-via-internal-function-calls-in-arrays

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