CVE-2025-26622

vyper is a Pythonic Smart Contract Language for the EVM. Vyper sqrt() builtin uses the babylonian method to calculate square roots of decimals. Unfortunately, improper handling of the oscillating final states may lead to sqrt incorrectly returning rounded up results. This issue is being addressed and a fix is expected in version 0.4.1. Users are advised to upgrade as soon as the patched release is available. There are no known workarounds for this vulnerability.

Weakness

The product performs a calculation that generates incorrect or unintended results that are later used in security-critical decisions or resource management.

Affected Software

Potential Mitigations

• Use languages, libraries, or frameworks that make it easier to handle numbers without unexpected consequences.
• Examples include safe integer handling packages such as SafeInt (C++) or IntegerLib (C or C++).
• Use languages, libraries, or frameworks that make it easier to handle numbers without unexpected consequences.
• Examples include safe integer handling packages such as SafeInt (C++) or IntegerLib (C or C++).

Related Attack Patterns

• https://cwe.mitre.org/data/definitions/128.html
• https://cwe.mitre.org/data/definitions/129.html

References

• https://github.com/vyperlang/vyper/pull/4486
• https://github.com/vyperlang/vyper/security/advisories/GHSA-2p94-8669-xg86