# CVE-2024-24561: Vyper's bounds check on built-in `slice()` function can be overflowed

Source: https://junglewise.ai/threats/cve-2024-24561-vyper-s-bounds-check-on-built-in-slice-function-can-be-overflowed  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2024-02-01  
License: CC BY 4.0 with a link back

CVE-2024-24561 · Severity: low · CVSS 3.1 · Published 2024-02-01

Vyper is a pythonic Smart Contract Language for the ethereum virtual machine. In versions 0.3.10 and earlier, the bounds check for slices does not account for the ability for start + length to overflow when the values aren't literals. If a slice() function uses a non-literal argument for the start or length variable, this creates the ability for an attacker to overflow the bounds check. This issue can be used to do OOB access to storage, memory or calldata addresses. It can also be used to corrupt the length slot of the respective array.

Technologies: [vyper (PyPI)](https://junglewise.ai/threats/technologies/vyper). Vendors: [PyPI](https://junglewise.ai/threats/vendors/pypi).

## Quick answers

**Is CVE-2024-24561 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2024-24561 being exploited in the wild.

**How severe is CVE-2024-24561?** Low severity, with a CVSS score of 3.1, published 1 February 2024.

**Which products and versions are affected?** vyper (PyPI) ECOSYSTEM:introduced=0,fixed=0.4.0, ECOSYSTEM:introduced=0,fixed=0.4.0b1.

**Is there a fix for CVE-2024-24561?** Yes. vyper (PyPI): upgrade to 0.4.0, 0.4.0b1 or later. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**Am I affected by CVE-2024-24561?** Check whether you run vyper (PyPI) at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## How to fix

- vyper (PyPI): upgrade to 0.4.0, 0.4.0b1 or later

  ```sh
  pip install "vyper>=0.4.0b1"
  ```


## Affected products

- vyper (PyPI) ECOSYSTEM:introduced=0,fixed=0.4.0, ECOSYSTEM:introduced=0,fixed=0.4.0b1

## Identifiers

- CVE-2024-24561
- GHSA-9x7f-gwxq-6f2c
- PYSEC-2024-149

## Related threats

- [Vyper memory corruption in nested function calls and tuples](https://junglewise.ai/threats/vyper-memory-corruption-using-function-calls-within-tuples-nested-calls-c0689acb)
- [Vyper stack corruption in complex type argument passing](https://junglewise.ai/threats/vyper-call-stack-corruption-when-passing-complex-type-containing-non-3deb0c30)
- [Vyper return statement in nested for loops causes revert](https://junglewise.ai/threats/vyper-return-inside-for-loop-more-than-1-level-deep-ee8a193d)
- [PYSEC-2026-2028 - Vyper's `slice()` may elide side-effects when output length is 0](https://junglewise.ai/threats/cve-2025-47774-vyper-s-slice-may-elide-side-effects-when-output-length-is-0)
- [PYSEC-2026-2029 - Vyper's `concat()` builtin may elide side-effects for zero-length arguments](https://junglewise.ai/threats/cve-2025-47285-vyper-s-concat-builtin-may-elide-side-effects-for-zero-length)