CVE-2024-24561: Vyper bounds check on built-in `slice()` function can be overflowed
Description
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.
Classification
CVE ID: CVE-2024-24561
CVSS Base Severity: CRITICAL
CVSS Base Score: 9.8
CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Affected Products
Vendor: vyperlang
Product: vyper
Exploit Prediction Scoring System (EPSS)
EPSS Score: 0.91% (probability of being exploited)
EPSS Percentile: 74.82% (scored less or equal to compared to others)
EPSS Date: 2025-06-27 (when was this score calculated)
Stakeholder-Specific Vulnerability Categorization (SSVC)
SSVC Exploitation: poc
SSVC Technical Impact: total
SSVC Automatable: true
References
https://nvd.nist.gov/vuln/detail/CVE-2024-24561https://github.com/vyperlang/vyper/security/advisories/GHSA-9x7f-gwxq-6f2c
https://github.com/vyperlang/vyper/issues/3756
https://github.com/vyperlang/vyper/blob/b01cd686aa567b32498fefd76bd96b0597c6f099/vyper/builtins/functions.py#L404-L457