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@embhorn embhorn commented Jan 14, 2026

Description

Problem

In TLS 1.3, wolfSSL was accepting client_certificate_type and server_certificate_type extensions in ServerHello messages, violating RFC 8446 Section 4.2.

Solution

Modified TLSX_Parse() in src/tls.c to properly validate the message type for these extensions:

TLS Version Allowed Message Types
TLS 1.3 client_hello, encrypted_extensions only
TLS 1.2 client_hello, server_hello

Fixes #9655

Testing

Reproducer in #9655

Checklist

  • added tests
  • updated/added doxygen
  • updated appropriate READMEs
  • Updated manual and documentation

@embhorn embhorn self-assigned this Jan 14, 2026
@embhorn embhorn requested a review from gasbytes January 14, 2026 22:39
@embhorn embhorn assigned wolfSSL-Bot and unassigned embhorn Jan 14, 2026
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[Bug]: client_certificate_type and server_certificate_type extensions accepted in ServerHello for TLS 1.3

2 participants