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.

Classification

CVE ID: CVE-2025-27105

CVSS Base Severity: LOW

CVSS Base Score: 2.3

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

Affected Products

Vendor: vyperlang

Product: vyper

Exploit Prediction Scoring System (EPSS)

EPSS Score: 0.05% (probability of being exploited)

EPSS Percentile: 10.86% (scored less or equal to compared to others)

EPSS Date: 2025-03-22 (when was this score calculated)

References

https://nvd.nist.gov/vuln/detail/CVE-2025-27105
https://github.com/vyperlang/vyper/security/advisories/GHSA-4w26-8p97-f4jp

Timeline