high
7.5
CWE
789
Advisory Published
CVE Published
Updated

CVE-2023-30837: Vyper storage allocator overflow

First published: Fri May 05 2023(Updated: )

### Impact The storage allocator does not guard against allocation overflows. This can result in vulnerabilities like the following: ```vyper owner: public(address) take_up_some_space: public(uint256[10]) buffer: public(uint256[max_value(uint256)]) @external def initialize(): self.owner = msg.sender @external def foo(idx: uint256, data: uint256): self.buffer[idx] = data ``` Per @toonvanhove, "An attacker can overwrite the owner variable by calling this contract with calldata: `0x04bc52f8 fffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff5 ffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff` (spaces inserted for readability) `0x04bc52f8` is the selector for `foo(uint256, uint256)`, and the last argument `fff...fff` is the new value for the owner variable." ### Patches patched in 0bb7203b584e771b23536ba065a6efda457161bb ### Workarounds _Is there a way for users to fix or remediate the vulnerability without upgrading?_ ### References _Are there any links users can visit to find out more?_

Credit: security-advisories@github.com security-advisories@github.com security-advisories@github.com

Affected SoftwareAffected VersionHow to fix
pip/vyper<0.3.8
0.3.8
Vyperlang Vyper<0.3.8
<0.3.8

Remedy

https://github.com/vyperlang/vyper/commit/0bb7203b584e771b23536ba065a6efda457161bb

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Reference Links

Frequently Asked Questions

  • What is CVE-2023-30837?

    CVE-2023-30837 is a vulnerability in the Vyper smart contract language for the EVM related to the storage allocator not guarding against allocation overflows.

  • How does CVE-2023-30837 impact the affected software?

    CVE-2023-30837 can result in vulnerabilities like buffer overflow, which can be exploited by attackers.

  • What is the severity of CVE-2023-30837?

    CVE-2023-30837 has a severity rating of high.

  • Which versions of Vyper are affected by CVE-2023-30837?

    Vyper versions up to but excluding 0.3.8 are affected by CVE-2023-30837.

  • How can I mitigate CVE-2023-30837?

    To mitigate CVE-2023-30837, make sure to update Vyper to version 0.3.8 or later.

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