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TI-2023-20502 Aliases CVE-2023-39363GHSA-5824-cm3x-3c38

Vyper incorrectly allocated named re-entrancy locks

Priority MEDIUM 41CWE-863Published · Updated

Key facts

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

Attack profile from CVSS 4.0 · CNA. Fix status from CNA and GitHub. Impact type from CWE-863.

Summary

Vyper is a Pythonic Smart Contract Language for the Ethereum Virtual Machine (EVM). In versions 0.2.15, 0.2.16 and 0.3.0, named re-entrancy locks are allocated incorrectly. Each function using a named re-entrancy lock gets a unique lock regardless of the key, allowing cross-function re-entrancy in contracts compiled with the susceptible versions. A specific set of conditions is required to result in misbehavior of affected contracts, specifically: a `.vy` contract compiled with `vyper` versions `0.2.15`, `0.2.16`, or `0.3.0`; a primary function that utilizes the `@nonreentrant` decorator with a specific `key` and does not strictly follow the check-effects-interaction pattern (i.e. contains an external call to an untrusted party before storage updates); and a secondary function that utilizes the same `key` and would be affected by the improper state caused by the primary function. Version 0.3.1 contains a fix for this issue.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00821 57th percentileScored 2026-11-07
Public exploit Yes 3 exploit referencesTagged by NVD
Fix Fixed vyper (PyPI): 0.3.1

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
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
vyperlangvyper= 0.2.15; = 0.2.16; = 0.3.0—No fix listedCNA
—vyper (PyPI)0.2.15 to before 0.3.10.3.1Patch availableGHSA-5824-cm3x-3c38
  • vyper Vendorvyperlang Affected = 0.2.15; = 0.2.16; = 0.3.0 Fixed in — No fix listed CNA
  • vyper (PyPI) Vendor— Affected 0.2.15 to before 0.3.1 Fixed in 0.3.1 Patch available GHSA-5824-cm3x-3c38

CPE configurations NVD · 3

CPEVersionsRoleVendor
cpe:2.3:a:vyperlang:vyper:0.2.15:*:*:*:*:python:*:*0.2.15Vulnerablevyperlang
cpe:2.3:a:vyperlang:vyper:0.2.16:*:*:*:*:python:*:*0.2.16Vulnerablevyperlang
cpe:2.3:a:vyperlang:vyper:0.3.0:*:*:*:*:python:*:*0.3.0Vulnerablevyperlang
  • cpe:2.3:a:vyperlang:vyper:0.2.15:*:*:*:*:python:*:* Versions 0.2.15 Vulnerable ·vyperlang
  • cpe:2.3:a:vyperlang:vyper:0.2.16:*:*:*:*:python:*:* Versions 0.2.16 Vulnerable ·vyperlang
  • cpe:2.3:a:vyperlang:vyper:0.3.0:*:*:*:*:python:*:* Versions 0.3.0 Vulnerable ·vyperlang

Remediation

  • Fix · GHSA-5824-cm3x-3c38 vyper (PyPI) Fixed in 0.3.1 Advisory →

Timeline

  1. 2026-10-02 Threatist record created from CVE-2023-39363
  2. 2026-10-03 Alias added: GHSA-5824-cm3x-3c38

References

Exploit 3

Patch 2

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