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CVE-2023-42441

17
FAUCET Score

CVE-2023-42441 is a medium-severity vulnerability affecting Vyper, a Pythonic Smart Contract Language for the Ethereum Virtual Machine (EVM), specifically versions 0.2.9 through 0.3.9. It stems from a flaw where non-empty string reentrancy locks (e.g., @nonreentrant("") or @nonreentrant('')) fail to perform runtime reentrancy checks, potentially leading to unexpected contract behavior. The vulnerability has a CVSS score of 5.3 (Medium) with a vector of AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N, indicating it can be exploited remotely with low complexity, resulting in a low impact on integrity without requiring user interaction. There is currently no evidence of active exploitation, public exploit code (Metasploit, Nuclei, ExploitDB), or significant community discussion or media coverage, suggesting a low immediate threat level.

Impacted Technologies

VendorProductVersion(s)CPE
>= 0.2.9, < 0.3.10CPE matchmatch criteria
cpe:2.3:a:vyperlang:vyper:*:*:*:*:*:python:*:*

CVSS Data

CVSS version used by this source: 3.1

5.3MEDIUM

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

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
NONE
Integrity Impact
LOW
Availability Impact
NONE
Exploitability Score
3.9
Impact Score
1.4
CvssVersion
3.1

Exploit Intelligence

EPSS Score
0.42%
Probability of exploitation in next 30 days
EPSS Percentile
34.7%
Percentile rank of EPSS score among Peer Group
As of 2026-07-27
Model: v2026.06.15
This CVE's current EPSS score of 0.0042 is in the 21st percentile among its peer group of 23,725 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.0 Reddit, 0.1 Bluesky, 0.0 Mastodon, and 0.4 GitHub mentions.

Media Mentions

No media coverage found for this CVE.

The average CVE in this peer group has 0.0 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (2)

github_advisorypatch availablevia nvd_reference
View patch
pippatch availablevia ghsa
Product: vyperFixed in: 0.3.10

Vendor Advisories (1)

pipGHSA-3hg2-r75x-g69mmedium

Vyper has incorrect re-entrancy lock when key is empty string

Sep 18, 2023

References

github.com / vyperlang/vyper/commit/0b740280c1e3c5528a20d47b29831948ddcc6d83
Patch
github.com / vyperlang/vyper/pull/3605
Issue TrackingPatch
github.com / vyperlang/vyper/security/advisories/GHSA-3hg2-r75x-g69m
ExploitPatchVendor Advisory