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VyperApplication · Vyperlang

CVE-2023-40015

MEDIUM · 5.3 CVSS v3.1 Published 2023-09-04
Fix available
A fix is available. Upgrade to after 0.3.9 or later.
See remediation →
62/100
Remediation priority · Elevated
Public exploit Remotely reachable No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis

A detailed technical summary for this CVE is being prepared.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
VyperApplication
Affected:<= 0.3.9

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
Low
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to a release after 0.3.9
Recommended fix High confidence
  1. Review all smart contracts compiled with Vyper <= 0.3.9 for expressions using: unsafe_add, unsafe_sub, unsafe_mul, unsafe_div, pow_mod256, bitwise operators (|, &, ^), raw_call, comparison operators (<, >, <=, >=, ==, !=), and enum membership tests (in, not in)
  2. Identify any cases where these operators have arguments that produce side effects such as: state-modifying external calls, state-modifying internal calls, raw_call, pop() on storage Dynamic Arrays, create_minimal_proxy_to, create_copy_of, or create_from_blueprint
  3. Refactor the code to ensure that arguments to these operators do not produce side effects, or if a side effect is necessary, ensure no other argument depends on that side effect
  4. Recompile the modified contracts with the same Vyper version or wait for an official patch

Generated from the published advisory — verify against the referenced sources before acting.

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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2023-40015 in production — separate from our analysis above.

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