Instituto Nacional de ciberseguridad. Sección Incibe
Instituto Nacional de Ciberseguridad. Sección INCIBE-CERT

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CVE-2025-15346

Severity CVSS v4.0:
CRITICAL
Type:
CWE-287 Authentication Issues
Publication date:
08/01/2026
Last modified:
08/01/2026

Description

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. <br /> <br /> 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. <br /> <br /> This results in improper authentication, allowing attackers to bypass mutual TLS (mTLS) client authentication by omitting a client certificate during the TLS handshake. <br /> <br /> The issue affects versions up to and including 5.8.2.

Impact

Vector 4.0
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/AU:Y CVSS v4.0 Severity and Metrics:

Base Score: 9.30 CRITICAL
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/AU:Y

Attack Vector (AV): Network
Attack Complexity (AC): Low
Attack Requirements (AT): None
Privileges Required (PR): None
User Interaction (UI): None
Confidentiality (VC): High
Integrity (VI): High
Availability (VA): None
Confidentiality (SC): None
Integrity (SI): None
Availability (SA): None
Automatable (AU): Yes

Base Score 4.0
9.30
Severity 4.0
CRITICAL

References to Advisories, Solutions, and Tools