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TI-2023-14856 Aliases CVE-2023-31146GHSA-3p37-3636-q8wv

Vyper vulnerable to OOB DynArray access when array is on both LHS and RHS of an assignment

Priority MEDIUM 48CWE-787Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
—
Confidentiality · integrity · availability
None · High · High
Fix status
Fixed

Attack profile from CVSS 3.1 · CISA ADP. Fix status from CNA and GitHub.

Summary

Vyper is a Pythonic smart contract language for the Ethereum virtual machine. Prior to version 0.3.8, during codegen, the length word of a dynarray is written before the data, which can result in out-of-bounds array access in the case where the dynarray is on both the lhs and rhs of an assignment. The issue can cause data corruption across call frames. The expected behavior is to revert due to out-of-bounds array access. Version 0.3.8 contains a patch for this issue.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.01252 69th percentileScored 2026-11-07
Public exploit Yes 1 exploit referenceTagged by NVD
Fix Fixed vyper (vyperlang): 0.3.8vyper (PyPI): 0.3.8

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
Yes
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
vyperlangvyperbefore 0.3.80.3.8Patch availableCNA
—vyper (PyPI)before 0.3.80.3.8Patch availableGHSA-3p37-3636-q8wv
  • vyper Vendorvyperlang Affected before 0.3.8 Fixed in 0.3.8 Patch available CNA
  • vyper (PyPI) Vendor— Affected before 0.3.8 Fixed in 0.3.8 Patch available GHSA-3p37-3636-q8wv

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:vyperlang:vyper:*:*:*:*:*:*:*:*before 0.3.8Vulnerablevyperlang
  • cpe:2.3:a:vyperlang:vyper:*:*:*:*:*:*:*:* Versions before 0.3.8 Vulnerable ·vyperlang

Remediation

  • Fix · CNA vyper (vyperlang) Fixed in 0.3.8
  • Fix · GHSA-3p37-3636-q8wv vyper (PyPI) Fixed in 0.3.8 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2023-31146
  2. 2026-10-03 Alias added: GHSA-3p37-3636-q8wv

References

Exploit 1

Patch 1

Advisory 1

Other 2

  • TI-2024-16182 Vyper bounds check on built-in `slice()` function can be overflowed CVSS 3.1CRITICAL 9.8
  • TI-2024-14992 concat built-in can corrupt memory in vyper CVSS 3.1CRITICAL 9.8
  • TI-2024-16184 Vyper array negative index vulnerability CVSS 3.1CRITICAL 9.8
  • TI-2022-08657 Integer bounds error in Vyper CVSS 3.1CRITICAL 9.8
  • TI-2022-11796 Multiple evaluation of contract address in call in vyper CVSS 3.1HIGH 8.2
  • TI-2024-21531 vyper performs double eval of the argument of sqrt CVSS 3.1MEDIUM 5.3
See all 37 →

Sources

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences