This issue was solved with changeset r41812.
Santiago, thank you for reporting this issue.
Your contribution to Ruby is greatly appreciated.
May Ruby be with you.
* lib/openssl/ssl.rb: Fix SSL client connection crash for SAN marked
critical.
The patch for CVE-2013-4073 caused SSL crash when a SSL server returns
the certificate that has critical SAN value. X509 extension could
include 2 or 3 elements in it:
[id, criticality, octet_string] if critical,
[id, octet_string] if not.
Making sure to pick the last element of X509 extension and use it as
SAN value.
[ruby-core:55685] [Bug #8575]
Thank you @nahi for providing the patch!