CVE-2023-42441 — Vyper is a Pythonic Smart Contract Language for the Ethereum Virtual Machine (EV

Vyper is a Pythonic Smart Contract Language for the Ethereum Virtual Machine (EVM). Starting in version 0.2.9 and prior to version 0.3.10, locks of the type `@nonreentrant("")` or `@nonreentrant('')` do not produce reentrancy checks at runtime. This issue is f

01What is this vulnerability?

Vyper is a Pythonic Smart Contract Language for the Ethereum Virtual Machine (EVM). Starting in version 0.2.9 and prior to version 0.3.10, locks of the type `@nonreentrant("")` or `@nonreentrant('')` do not produce reentrancy checks at runtime. This issue is fixed in version 0.3.10. As a workaround, ensure the lock name is a non-empty string.

02Affected products

No structured affected-product list available — see references below for vendor advisories.

03Active exploitation status

Not currently listed on the CISA Known Exploited Vulnerabilities (KEV) catalog. EPSS is the best forward-looking signal — see the EPSS row above.

04Recommended remediation

• Patch to a fixed version listed in the vendor advisory (see references below).
• Mitigate with WAF rules, network egress filters, or feature flags where the patch is not yet available.
• Hunt historical logs for exploitation indicators — see Detection signatures below.

05Technical details

For the full vendor write-up, exploit chains, and reference implementations, see the references list in section 09.

06Detection signatures

Ask SARA in chat to draft a starting detection for this CVE in your stack of choice.

07Related CVEs

No directly-cited follow-up CVEs in the KB record for this advisory. The references list in section 09 carries the vendor cross-references.

08Timeline

• Published: 2023-09-18 (2y 10m ago)
• Last modified: 2026-06-17

09References

No additional references available in the KB record.