CVE-2023-42460 _abi_decode input not validated in complex expressions in Vyper
Vyper compiler fails to validate _abi_decode inputs in nested expressions, allowing bounds checking bypass and incorrect contract results.
- Exploited in the wild
- Not known
- Login needed
- Any signed-in user
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-42460?
CVE-2023-42460 is a medium-severity vulnerability in vyperlang vyper, published on 26 Sep 2023. Any signed-in user can exploit it over the network, with no action from the victim.
Official description
Vyper is a Pythonic Smart Contract Language for the EVM. The `_abi_decode()` function does not validate input when it is nested in an expression. Uses of `_abi_decode()` can be constructed which allow for bounds checking to be bypassed resulting in incorrect results. This issue has not yet been fixed, but a fix is expected in release `0.3.10`. Users are advised to reference pull request #3626.
Weakness: CWE-682
Which versions are affected by CVE-2023-42460?
3 open source packages ship an affected version, including vyper. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
vyper PyPI | From 0.3.4 | 0.3.10 |
vyper PyPI | From 0.3.4 | 0.3.10 |
vyper PyPI | From 0.3.4 | 0.3.10 |
Products include Vyperlang Vyper.
How do I fix CVE-2023-42460?
Upgrade vyper to 0.3.10 or later.
Is CVE-2023-42460 being exploited?
There is no known exploitation of CVE-2023-42460 in the wild and no public exploit code.
Other vulnerabilities in vyperlang vyper
- CVE-2024-24563 Vyper array negative index vulnerability
- CVE-2024-24561 Vyper bounds check on built-in `slice()` function can be overflowed
- CVE-2023-39363 Vyper incorrectly allocated named re-entrancy locks
- CVE-2022-24845 Integer bounds error in Vyper
- CVE-2022-29255 Multiple evaluation of contract address in call in vyper
Sources
Also known as GHSA-cx2q-hfxr-rj97, PYSEC-2023-191.