CVE-2024-32481 – vyper

Package

Manager: pip
Name: vyper
Vulnerable Version: >=0.3.8 <0.4.0

Severity

Level: Medium

CVSS v3.1: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

CVSS v4.0: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N

EPSS: 0.01172 pctl0.77896

Details

vyper's range(start, start + N) reverts for negative numbers ### Summary When looping over a `range` of the form `range(start, start + N)`, if `start` is negative, the execution will always revert. ### Details This issue is caused by an incorrect assertion inserted by the code generation of the range (`stmt.parse_For_range()`): https://github.com/vyperlang/vyper/blob/9136169468f317a53b4e7448389aa315f90b95ba/vyper/codegen/stmt.py#L286-L287 This assertion was introduced in https://github.com/vyperlang/vyper/commit/3de1415ee77a9244eb04bdb695e249d3ec9ed868 to fix https://github.com/advisories/GHSA-6r8q-pfpv-7cgj. 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. ### PoC ```Vyper @external def foo(): x:int256 = min_value(int256) # revert when it should not since we have the following assertion that fails: # [assert, [le, min_value(int256), max_value(int256) + 1 - 10]], for i in range(x, x + 10): pass ``` ### Patches patched in v0.4.0, specifically, https://github.com/vyperlang/vyper/pull/3679 disallows this form of `range()`. ### Impact 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.

Metadata

Created: 2024-04-25T19:53:43Z
Modified: 2024-04-25T19:53:43Z
Source: https://github.com/github/advisory-database/blob/main/advisories/github-reviewed/2024/04/GHSA-ppx5-q359-pvwj/GHSA-ppx5-q359-pvwj.json
CWE IDs: ["CWE-681"]
Alternative ID: GHSA-ppx5-q359-pvwj
Finding: F113
Auto approve: 1