---
id: CVE-2025-15346
title: "A vulnerability in the handling of verify_mode = CERT_REQUIRED in the wolfssl Python package (wolfssl-py) causes client certificate requirements to not be fully enforced.\_\n\nBecause the WOLFSSL_VERIFY_FAIL_IF_NO_PEER_CERT flag was not inc…"
summary: "A vulnerability in the handling of verify_mode = CERT_REQUIRED in the wolfssl Python package (wolfssl-py) causes client certificate requirements to not be fully enforced.\_\n\nBecause the WOLFSSL_VERIFY_FAIL_IF_NO_PEER_CERT flag was not inc…"
severity: none
cwe:
  - CWE-287
  - CWE-306
published: '2026-01-08'
updated: '2026-09-30'
sourceUpdated: '2026-09-30T23:10:00.237'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2025-15346'
references:
  - url: >-
      https://github.com/wolfSSL/wolfssl-py/commit/b4517dece79f682a8f453abce5cfc0b81bae769d
    label: facts@wolfssl.com
  - url: 'https://github.com/wolfSSL/wolfssl-py/pull/62'
    label: facts@wolfssl.com
  - url: 'https://github.com/wolfSSL/wolfssl-py/releases/tag/v5.8.4-stable'
    label: facts@wolfssl.com
tags:
  - nvd
epss: 0.00338
epssPercentile: 0.24839
ingestedAt: '2026-09-30T23:29:32.558Z'
---

## Overview

A vulnerability in the handling of verify_mode = CERT_REQUIRED in the wolfssl Python package (wolfssl-py) causes client certificate requirements to not be fully enforced. 

Because the WOLFSSL_VERIFY_FAIL_IF_NO_PEER_CERT flag was not included, the behavior effectively matched CERT_OPTIONAL: a peer certificate was verified if presented, but connections were incorrectly authenticated when no client certificate was provided. 

This results in improper authentication, allowing attackers to bypass mutual TLS (mTLS) client authentication by omitting a client certificate during the TLS handshake. 

The issue affects versions up to and including 5.8.2.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.