CVE-2023-39363
MediumCVSS 5.9Exploitation Probability (EPSS)
Low risk48th percentile - higher than 48% of all known CVEs
Summary
Versions 0.2.15, 0.2.16, and 0.3.0 of the Vyper language have a flaw in the allocation of named re-entrancy locks, allowing cross-function re-entrancy in contracts. Version 0.3.1 contains a fix for this issue.
Risk Assessment
Organizations using vulnerable versions of Vyper may be exposed to re-entrancy attacks, potentially leading to unauthorized operations in contracts. This could result in loss of funds or data.
Recommendation
It is recommended to upgrade to Vyper version 0.3.1 or later to mitigate this vulnerability. Existing contracts should also be reviewed for potential security gaps.
Original NVD description (English source)
Vyper is a Pythonic Smart Contract Language for the Ethereum Virtual Machine (EVM). In versions 0.2.15, 0.2.16 and 0.3.0, named re-entrancy locks are allocated incorrectly. Each function using a named re-entrancy lock gets a unique lock regardless of the key, allowing cross-function re-entrancy in contracts compiled with the susceptible versions. A specific set of conditions is required to result in misbehavior of affected contracts, specifically: a `.vy` contract compiled with `vyper` versions `0.2.15`, `0.2.16`, or `0.3.0`; a primary function that utilizes the `@nonreentrant` decorator with a specific `key` and does not strictly follow the check-effects-interaction pattern (i.e. contains an external call to an untrusted party before storage updates); and a secondary function that utilizes the same `key` and would be affected by the improper state caused by the primary function. Version 0.3.1 contains a fix for this issue.