CVE-2023-32059Public exploitNetwork attack vector

Smart-contract logic corruption via misordered default arguments

Published May 11, 2023 · Updated Jan 24, 2025

Incorrect argument ordering in Vyper before 0.3.8 allows attackers to trigger unintended smart-contract behavior after compilation. The lookup_internal_function alignment routine takes default values from the start of the list, so partially supplied calls receive leftmost rather than remaining rightmost defaults and can bypass type checking. Affected source must define an internal function with multiple defaults and omit some arguments; the compiled contract can then consume an unintended value.

CVSS severity7.5
High
EPSS probability0.73%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Incorrect argument ordering in Vyper before 0.3.8 allows attackers to trigger unintended smart-contract behavior after compilation. The lookup_internal_function alignment routine takes default values from the start of the list, so partially supplied calls receive leftmost rather than remaining rightmost defaults and can bypass type checking. Affected source must define an internal function with multiple defaults and omit some arguments; the compiled contract can then consume an unintended value.

The record

CVE
CVE-2023-32059
Published
May 11, 2023
Updated
Jan 24, 2025
Vendor
Vyper
Product
Vyper
Classifications
CWE-683
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. May 11, 2023CVE publishedPublication date reported by the CVE source.
  2. Jan 24, 2025Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=< 0.3.8

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Vyper · Vyperversion=< 0.3.8

Published CVSS scores

7.5GitHub, Inc.CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
7.5CISA-ADPCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitPublished

Weakness, pattern, technique

CWE-683Function Call With Incorrect Order of Arguments

Public exploit references

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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