CVE-2021-48019

medium

Description

Vyper before 0.2.9 deploys forwarder proxies through the built-in create_forwarder_to function that report a fixed 4096-byte RETURNDATASIZE rather than the actual return data size. Calls through these proxies can yield corrupted data when a function returns more than 4096 bytes without return data sanitation, and fail strict return-size checks such as SafeERC20.safeTransfer.

References

https://www.vulncheck.com/advisories/vyper-before-0.2.9-incorrect-returndatasize-in-create-forwarder-to-proxies

https://github.com/vyperlang/vyper/security/advisories/GHSA-375m-5fvv-xq23

https://euvd.enisa.europa.eu/vulnerability/EUVD-2021-34889

Details

Source: Mitre, NVD

Published: 2026-10-21

Updated: 2026-10-21

Risk Information

CVSS v2

Base Score: 4

Vector: CVSS2#AV:N/AC:H/Au:N/C:N/I:P/A:P

Severity: Medium

CVSS v3

Base Score: 4.8

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

Severity: Medium

CVSS v4

Base Score: 6.3

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

Severity: Medium

EPSS

EPSS: 0.00248