Cyber Resilience

CVE-2023-39363

Access Control in Vyperlang Vyper 0.2.15 … 0.3.0

Public PoCAccess Control
Published
07 August 2023
Modified
21 November 2024
Patch / advisory
View advisory
CVSS Score v4 9.1
Click a component to see what it means
Raw vectorCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:H/VA:H/SC:N/SI:H/SA:H/E:A/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0082 54th percentile
Risk Priority 47 floored blend · peak EPSS

Summary

CVE-2023-39363 is a critical-severity Incorrect Authorization (CWE-863) vulnerability in Vyperlang Vyper. Its CVSS base score is 9.1 (Critical).

Operationally, exploitation aligns with the MITRE ATT&CK technique Exploitation for Privilege Escalation (T1068); ranked in the top 46% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

OWASP Top 10 for Web (2025)

A01:2025 Broken Access Control

EU & UK References

Vulnerability Data

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,…

more

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.

CWE(s)
CWE-863

Related Threats

MITRE ATT&CK Enterprise Techniques

T1068 Exploitation for Privilege Escalation Privilege Escalation
Adversaries may exploit software vulnerabilities in an attempt to elevate privileges.
attack.mitre.org →
T1548 Abuse Elevation Control Mechanism Privilege Escalation
Adversaries may circumvent mechanisms designed to control privilege elevation to gain higher-level permissions.
attack.mitre.org →
T1548.002 Bypass User Account Control Privilege Escalation
Adversaries may bypass UAC mechanisms to elevate process privileges on system.
attack.mitre.org →
T1548.003 Sudo and Sudo Caching Privilege Escalation
Adversaries may perform sudo caching and/or use the sudoers file to elevate privileges.
attack.mitre.org →
T1190 Exploit Public-Facing Application Initial Access
Adversaries may attempt to exploit a weakness in an Internet-facing host or system to initially access a network.
attack.mitre.org →
T1210 Exploitation of Remote Services Lateral Movement
Adversaries may exploit remote services to gain unauthorized access to internal systems once inside of a network.
attack.mitre.org →
Derived from this CVE’s CWE(s) via the direct CWE→ATT&CK cross-walk.

CVEs Like This One

CVE-2023-32058Same product: Vyperlang Vyper
CVE-2023-42460Same product: Vyperlang Vyper
CVE-2024-32645Same product: Vyperlang Vyper
CVE-2024-32646Same product: Vyperlang Vyper
CVE-2024-32481Same product: Vyperlang Vyper
CVE-2025-26622Same product: Vyperlang Vyper
CVE-2023-46247Same product: Vyperlang Vyper
CVE-2023-37902Same product: Vyperlang Vyper
CVE-2024-24564Same product: Vyperlang Vyper
CVE-2024-26149Same product: Vyperlang Vyper

Affected Assets

vyperlang
vyper
0.2.15, 0.2.16, 0.3.0

Mitigating Controls

Control response

Prevent
Stop it (NIST 800-53)

—

Detect
Catch it (NIST detect / respond)

—

Harden
Shrink the surface (DISA STIG)
  • 5 hardening rules · 3 OS baselines
Validate
Prove the fix (OWASP ASVS)

—

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

AC-1 Policy and Procedures
addresses: CWE-863

Periodic review and update of procedures reduces incorrect authorization implementations over time.

AC-13 Supervision and Review — Access Control
addresses: CWE-863

Supervision identifies cases where authorization logic incorrectly permits unauthorized actions.

AC-16 Security and Privacy Attributes
addresses: CWE-863

Defining permitted attribute values and auditing modifications reduces the chance of incorrect authorization outcomes due to tampered or missing labels.

AC-17 Remote Access
addresses: CWE-863

The authorization process and usage restrictions help prevent incorrect authorization for remote access types.

AC-18 Wireless Access
addresses: CWE-863

Establishing configuration and connection requirements helps ensure correct rather than incorrect authorization for wireless access.

AC-19 Access Control for Mobile Devices
addresses: CWE-863

Establishing connection authorization processes for mobile devices helps ensure authorization decisions are correctly implemented rather than incorrect.

AC-2 Account Management
addresses: CWE-863

Monitoring account use, notifying on changes, and reviewing accounts for compliance corrects incorrect authorization assignments.

AC-20 Use of External Systems
addresses: CWE-863

Ensures authorization decisions for external system use are correctly implemented and enforced.

Mitigating Controls (NIST CSF 2.0) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.

PR.AA-05 mostly match
prevents

Defining, enforcing, and reviewing access authorizations and least privilege directly prevents incorrect authorization checks.

Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI

Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.

A.5.15 Access control partial match
prevents

Requiring consistency between access rights and classification plus formal approval steps ensures that the authorization logic correctly distinguishes between entities that should and should not be granted access.

A.5.18 Access rights partial match
prevents

Enforcing policy-driven approval and role-change reviews stops incorrect or stale authorization decisions from remaining in effect after job changes or terminations.

A.8.3 Information access restriction partial match
prevents

By tying access rights to identity, device, location and classification, the control reduces the likelihood that an authorization decision will be based on an incorrect or bypassed policy.

Hardening callouts derived

Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).

Oracle Linux 8 (2 rules)
  • V-248581 OL 8 must require users to provide a password for privilege escalation. prevents CWE-863
  • V-252656 The OL 8 operating system must not be configured to bypass password requirements for privilege escalation. prevents CWE-863
RHEL 7 (1 rule)
  • V-204430 The Red Hat Enterprise Linux operating system must be configured so that users must re-authenticate for privilege escalation. prevents CWE-863
RHEL 8 (1 rule)
  • V-251712 The RHEL 8 operating system must not be configured to bypass password requirements for privilege escalation. prevents CWE-863

References