CVE-2023-37902 Vyper's ecrecover can return undefined data if signature does not verify

What is CVE-2023-37902?

CVE-2023-37902 is a medium-severity vulnerability in vyperlang vyper, published on 25 Jul 2023. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

Vyper is a Pythonic programming language that targets the Ethereum Virtual Machine (EVM). Prior to version 0.3.10, the ecrecover precompile does not fill the output buffer if the signature does not verify. However, the ecrecover builtin will still return whatever is at memory location 0. This means that the if the compiler has been convinced to write to the 0 memory location with specially crafted data (generally, this can happen with a hashmap access or immutable read) just before the ecrecover, a signature check might pass on an invalid signature. Version 0.3.10 contains a patch for this issue.

Weakness: CWE-252

Which versions are affected by CVE-2023-37902?

3 open source packages ship an affected version, including vyper. It affects 1 product.

Products include Vyperlang Vyper.

How do I fix CVE-2023-37902?

Upgrade vyper to a fixed version for your release line: 0.3.10 or 0.3.9.

Is CVE-2023-37902 being exploited?

There is no known exploitation of CVE-2023-37902 in the wild and no public exploit code.

Other vulnerabilities in vyperlang vyper

• CVE-2024-24563 Vyper array negative index vulnerability Critical 9.8
• CVE-2024-24561 Vyper bounds check on built-in `slice()` function can be overflowed Critical 9.8
• CVE-2023-39363 Vyper incorrectly allocated named re-entrancy locks Critical 9.1
• CVE-2022-24845 Integer bounds error in Vyper High 8.8
• CVE-2022-29255 Multiple evaluation of contract address in call in vyper High 8.2

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as GHSA-f5x6-7qgp-jhf3, PYSEC-2023-133.