# CVE-2024-26149: Vyper's `_abi_decode` vulnerable to Memory Overflow

Source: https://junglewise.ai/threats/cve-2024-26149-vyper-s-abi-decode-vulnerable-to-memory-overflow  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2024-02-26  
License: CC BY 4.0 with a link back

CVE-2024-26149 · Severity: low · CVSS 3.1 · Published 2024-02-26

Vyper is a pythonic Smart Contract Language for the ethereum virtual machine. If an excessively large value is specified as the starting index for an array in `_abi_decode`, it can cause the read position to overflow. This results in the decoding of values outside the intended array bounds, potentially leading to exploitations in contracts that use arrays within `_abi_decode`. This vulnerability affects 0.3.10 and earlier versions.

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

## Quick answers

**Is CVE-2024-26149 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2024-26149 being exploited in the wild.

**How severe is CVE-2024-26149?** Low severity, with a CVSS score of 3.1, published 26 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-2024-26149?** 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-2024-26149?** 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-2024-26149
- GHSA-9p8r-4xp4-gw5w
- PYSEC-2024-164

## 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)