CVE-2025-27105

CRITICAL

vyperlang/vyper < 0.4.1 - Out-of-bounds Write via DynArray AugAssign Statement

Title source: llm
STIX 2.1

Description

vyper is a Pythonic Smart Contract Language for the EVM. Vyper handles AugAssign statements by first caching the target location to avoid double evaluation. However, in the case when target is an access to a DynArray and the rhs modifies the array, the cached target will evaluate first, and the bounds check will not be re-evaluated during the write portion of the statement. This issue has been addressed in version 0.4.1 and all users are advised to upgrade. There are no known workarounds for this vulnerability.

References (1)

Core 1
Core References

Scores

CVSS v3 9.1
EPSS 0.0033
EPSS Percentile 55.6%
Attack Vector NETWORK
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H

CISA SSVC

Vulnrichment
Exploitation none
Automatable yes
Technical Impact partial

Details

CWE
CWE-787
Status published
Products (2)
pypi/vyper 0 - 0.4.1PyPI
vyperlang/vyper < 0.4.1
Published Feb 21, 2025
Tracked Since Feb 18, 2026