CVE-2023-40015

What it is

Vyper is a Pythonic Smart Contract Language. For the following (probably non-exhaustive) list of expressions, the compiler evaluates the arguments from right to left instead of left to right. `unsafe_add, unsafe_sub, unsafe_mul, unsafe_div, pow_mod256, |, &, ^ (bitwise operators), bitwise_or (deprecated), bitwise_and (deprecated), bitwise_xor (deprecated), raw_call, <, >, <=, >=, ==, !=, in, not in (when lhs and rhs are enums)`. This behaviour becomes a problem when the evaluation of one of the arguments produces side effects that other arguments depend on. The following expressions can produce side-effect: state modifying external call , state modifying internal call, `raw_call`, `pop()` when used on a Dynamic Array stored in the storage, `create_minimal_proxy_to`, `create_copy_of`, `create_from_blueprint`. This issue has not yet been patched. Users are advised to make sure that the arguments of the expression do not produce side effects or, if one does, that no other argument is dependent on those side effects.

At a glance

Exploitability

Can be exploited over the network without logging in. Limited direct impact.

Exploit odds

0.5% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2023-09-04 18:15 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-06-17 06:15 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.5% in the next 30 days (EPSS).
• Severity: 3.7 LOW (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2023-09-04 18:15 UTC

Last modified

2026-06-17 06:15 UTC

Exploit probability

0.5% · EPSS, next 30 days

Weakness

CWE-670

Record status

Modified

Affected

• Vyperlang Vyper ≤ 0.3.9

Attack profile CVSS 3.1 · 3.7

Attack vector

Network

Complexity

High

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

Low

Availability

None

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2023-40015.md and follow it. Check whether this project is affected by CVE-2023-40015. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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