CVE-2023-40015 Vyper: reversed order of side effects for some operations
Vyper compiler evaluates certain operations right-to-left, causing logic errors when arguments have side effects, impacting smart contract security.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- Available
What is CVE-2023-40015?
CVE-2023-40015 is a low-severity vulnerability in vyperlang vyper, published on 4 Sep 2023. 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 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.
Weakness: CWE-670
Which versions are affected by CVE-2023-40015?
3 open source packages ship an affected version, including vyper. It affects 1 product.
| Package | Affected | Fixed in |
|---|---|---|
vyper PyPI | All versions to 0.4.2 | None |
vyper PyPI | All versions to 0.4.2 | None |
vyper PyPI | All versions | 0.3.10rc1 |
Products include Vyperlang Vyper.
How do I fix CVE-2023-40015?
Upgrade vyper to 0.3.10rc1 or later.
Is CVE-2023-40015 being exploited?
There is no known exploitation of CVE-2023-40015 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-g2xh-c426-v8mf, PYSEC-2023-167.