CVE-2024-24560 Vyper external calls can overflow return data to return input buffer
Attackers can exploit buffer overlap in Vyper external calls to read dirty input buffer data as return data, potentially leading to logic errors or code execution in smart contracts.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2024-24560?
CVE-2024-24560 is a low-severity memory corruption vulnerability in vyperlang vyper, published on 2 Feb 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
Vyper is a Pythonic Smart Contract Language for the Ethereum Virtual Machine. When calls to external contracts are made, we write the input buffer starting at byte 28, and allocate the return buffer to start at byte 0 (overlapping with the input buffer). When checking RETURNDATASIZE for dynamic types, the size is compared only to the minimum allowed size for that type, and not to the returned value's length. As a result, malformed return data can cause the contract to mistake data from the input buffer for returndata. When the called contract returns invalid ABIv2 encoded data, the calling contract can read different invalid data (from the dirty buffer) than the called contract returned.
Weakness: CWE-119
Which versions are affected by CVE-2024-24560?
3 open source packages ship an affected version, including vyper. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
vyper PyPI | All versions | 0.4.0 |
vyper PyPI | All versions | 0.4.0 |
vyper PyPI | All versions | 0.4.0b1 |
Products include Vyperlang Vyper.
How do I fix CVE-2024-24560?
Upgrade vyper to a fixed version for your release line: 0.4.0 or 0.4.0b1.
Upgrade to the fixed version. Memory-safe languages, compiler hardening and fuzzing prevent most new cases. More about Memory corruption.
Is CVE-2024-24560 being exploited?
It is not confirmed as exploited in the wild, but public exploit code for CVE-2024-24560 exists.
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-gp3w-2v2m-p686, PYSEC-2024-148.