2.6.5 fixes:
* CVE-2019-16255: A code injection vulnerability of Shell#[] and Shell#test
* CVE-2019-16254: HTTP response splitting in WEBrick (Additional fix)
* CVE-2019-15845: A NUL injection vulnerability of File.fnmatch and File.fnmatch?
* CVE-2019-16201: Regular Expression Denial of Service vulnerability of WEBrick’s Digest access authentication

2.6.4 fixes:
* Multiple jQuery vulnerabilities in RDoc

Changelog: https://github.com/ruby/ruby/compare/v2_6_3...v2_6_5

Signed-off-by: Luiz Angelo Daros de Luca <luizluca@gmail.com>