Open-Source Security Intelligence

Know every vulnerability
before it knows you.

DevGuard continuously monitors your dependencies and alerts you when CVEs like this one affect your stack — with real-time threat intelligence built for developers.

Search

GHSA-m2v9-w374-5hj9

MediumCVSS 5.3 / 10
Published Apr 25, 2024·Last modified Feb 4, 2026
Affected Components(0)

No affected components available

Description

Summary

Prior to v0.3.0, __default__() functions did not respect the @nonreentrancy decorator and the lock was not emitted. This is a known bug and was already visible in the issue tracker (https://github.com/vyperlang/vyper/issues/2455), but it is being re-issued as an advisory so that tools relying on the advisory publication list can incorporate it into their searches.

A contract search was additionally performed and no vulnerable contracts were found in production.

PoC

@external
@payable
@nonreentrant("default")
def __default__():
    pass

after codegen:

[seq,
  [if, [lt, calldatasize, 4], [goto, fallback]],
  [mstore, 28, [calldataload, 0]],
  [with, _func_sig, [mload, 0], seq],
  [seq_unchecked,
    [label, fallback],
    [seq,
      pass,
      # Line 5
      pass,
      pass,
      # Line 4
      stop]]],

Impact

No vulnerable production contracts were found. Additionally, using a lock on a default function is a very sparsely used pattern. As such, the impact is low.

Risk Scores
Base Score
5.3

The vulnerability can be exploited over the network without needing physical access. It is easy for an attacker to exploit this vulnerability. An attacker does not need any special privileges or access rights. No user interaction is needed for the attacker to exploit this vulnerability. The impact is confined to the system where the vulnerability exists. There is a low impact on the integrity of the data.

Threat Intelligence
4.9

Exploitation attempts have been detected. Elevated vigilance and prompt remediation are advised.

EPSS
0.41%

The exploit probability is very low. The vulnerability is unlikely to be exploited in the next 30 days.

Exploit
Not available

We did not find any exploit available. Neither in GitHub repositories nor in the Exploit-Database.

Browse More

Scan your project

Continuously monitor your dependencies and get alerted when vulnerabilities like this one affect your stack.

Checkout DevGuard