Vulnerability · Published Feb 21, 2025 · Assigned by GitHub_M
CVE-2025-27105AugAssign evaluation order causing OOB write within the object in Vyper
Critical 9.1
In plain English
A critical-severity out-of-bounds write in vyper from vyperlang. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 47% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.
Official 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.
Affected packages & fixed versions
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| PyPI | vyper | 0.4.1 | GHSA-4w26-8p97-f4jp |
| PyPI | vyper | 0.4.1 | PYSEC-2025-31 |
Affected products (as reported)
Weakness: CWE-787 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
References
- https://github.com/vyperlang/vyper/security/advisories/GHSA-4w26-8p97-f4jp x_refsource_CONFIRM