// For flags

CVE-2025-15346

wolfSSL Python library `CERT_REQUIRED` mode fails to enforce client certificate requirement

Severity Score

9.3
*CVSS v4

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

Attend
*SSVC
Descriptions

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.

*Credits: Matan Radomski
CVSS Scores
Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
None
System
Vulnerable | Subsequent
Confidentiality
High
None
Integrity
High
None
Availability
None
None
Attack Vector
Network
Attack Complexity
Low
Attack Requirements
None
Privileges Required
None
User Interaction
None
System
Vulnerable | Subsequent
Confidentiality
High
None
Integrity
High
None
Availability
None
None
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High
Attack Vector
Network
Attack Complexity
Low
Authentication
None
Confidentiality
Partial
Integrity
Partial
Availability
Partial
* Common Vulnerability Scoring System
SSVC
  • Decision:Attend
Exploitation
None
Automatable
Yes
Tech. Impact
Total
* Organization's Worst-case Scenario
Timeline
  • 2025-12-29 CVE Reserved
  • 2026-01-07 CVE Published
  • 2026-01-08 CVE Updated
  • 2026-05-09 EPSS Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-287: Improper Authentication
  • CWE-306: Missing Authentication for Critical Function
CAPEC
  • CAPEC-115: Authentication Bypass
  • CAPEC-220: Client-Server Protocol Manipulation
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
WolfSSL
Search vendor "WolfSSL"
 WolfSSL-py
Search vendor "WolfSSL" for product "WolfSSL-py"
 >= 5.3.0 <= 5.8.2
Search vendor "WolfSSL" for product "WolfSSL-py" and version " >= 5.3.0 <= 5.8.2"
en
Affected