CVE-2024-32481
vyper's range(start, start + N) reverts for negative numbers
Description
Vyper is a pythonic Smart Contract Language for the Ethereum virtual machine. Starting in version 0.3.8 and prior to version 0.4.0b1, when looping over a `range` of the form `range(start, start + N)`, if `start` is negative, the execution will always revert. This issue is caused by an incorrect assertion inserted by the code generation of the range `stmt.parse_For_range()`. The issue arises when `start` is signed, instead of using `sle`, `le` is used and `start` is interpreted as an unsigned integer for the comparison. If it is a negative number, its 255th bit is set to `1` and is hence interpreted as a very large unsigned integer making the assertion always fail. Any contract having a `range(start, start + N)` where `start` is a signed integer with the possibility for `start` to be negative is affected. If a call goes through the loop while supplying a negative `start` the execution will revert. Version 0.4.0b1 fixes the issue.
How to fix CVE-2024-32481
To remediate CVE-2024-32481, upgrade the affected package to a fixed version below.
- —upgrade to 0.4.0 or later
- —upgrade to 0.4.0b1 or later
Is CVE-2024-32481 being exploited?
Low — EPSS is 1.5%, meaning exploitation activity has not been observed at scale.
Affected packages (2)
- >= 0.3.8, < 0.4.0
- >= 0.3.8, < 0.4.0b1
CVSS scores
| Source | Version | Severity | Vector |
|---|---|---|---|
| osv | CVSS 3.1 | MEDIUM5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N |