We are pleased to announce the release of Ruby 2.4.2.
This release contains some security fixes.

* [CVE-2017-0898: Buffer underrun vulnerability in Kernel.sprintf](/en/news/2017/09/14/sprintf-buffer-underrun-cve-2017-0898/)
* [CVE-2017-10784: Escape sequence injection vulnerability in the Basic authentication of WEBrick](/en/news/2017/09/14/webrick-basic-auth-escape-sequence-injection-cve-2017-10784/)
* [CVE-2017-14033: Buffer underrun vulnerability in OpenSSL ASN1 decode](/en/news/2017/09/14/openssl-asn1-buffer-underrun-cve-2017-14033/)
* [CVE-2017-14064: Heap exposure in generating JSON](/en/news/2017/09/14/json-heap-exposure-cve-2017-14064/)
* [Multiple vulnerabilities in RubyGems](/en/news/2017/08/29/multiple-vulnerabilities-in-rubygems/)
* Update bundled libyaml to version 0.1.7.

There are also many bug-fixes.
See [commit logs](https://github.com/ruby/ruby/compare/v2_4_1...v2_4_2) for more details.

## Known Problem

_(This section was added at September 15, 2017.)_

An incompatibility has been found for Ruby 2.4.2.
Ruby 2.4.2 can not link with libgmp nor jemalloc.
We will fix this problem with the next release, but if you are facing the problem now and need to overcome it immediately, get a patch from this link:

* [Ruby 2.4.2 and 2.3.5 cannot link with libgmp nor jemalloc](https://bugs.ruby-lang.org/issues/13899)

## Download

* <https://cache.ruby-lang.org/pub/ruby/2.4/ruby-2.4.2.tar.bz2>

      SIZE:   12607283 bytes
      SHA1:   a8a50a9297ff656e5230bf0f945acd69cc02a097
      SHA256: 08e72d0cbe870ed1317493600fbbad5995ea3af2d0166585e7ecc85d04cc50dc
      SHA512: 1a5302d2558089a6b91b815fff9b75a29e690f10861de5fdd48211f3f45025a70dad7495f216e6af9c62d72e69ed316f1a52fada704bdc7e6d8c094d141ea77c

* <https://cache.ruby-lang.org/pub/ruby/2.4/ruby-2.4.2.tar.gz>

      SIZE:   14187859 bytes
      SHA1:   b096124469e31e4fc3d00d2b61b11d36992e6bbd
      SHA256: 93b9e75e00b262bc4def6b26b7ae8717efc252c47154abb7392e54357e6c8c9c
      SHA512: 96c236bdcd09b2e7cf429da631a487fc00f1255443751c03c8abeb4c2ce57079ad60ef566fecc0bf2c7beb2f080e2b8c4d30f321664547b2dc7d2a62aa1075ef

* <https://cache.ruby-lang.org/pub/ruby/2.4/ruby-2.4.2.tar.xz>

      SIZE:   10046412 bytes
      SHA1:   8373e32c63bba2180799da091b572664aa9faf6f
      SHA256: 748a8980d30141bd1a4124e11745bb105b436fb1890826e0d2b9ea31af27f735
      SHA512: c1d42272fb0d94b693452e703b0ea4942bf59cbd4b08ba83bf039f54be97ebc88511632413da0164970b4cf97bc302bccb88aab48edfa8fa147498e7ee741595

* <https://cache.ruby-lang.org/pub/ruby/2.4/ruby-2.4.2.zip>

      SIZE:   15645325 bytes
      SHA1:   861b51de9db0d822ef141ad04383c76aa3cd2fff
      SHA256: 37d7cb27d8abd4b143556260506306659930548652343076f7f8470f07818824
      SHA512: 234765091528be1310ac315868f84ae6c505aa696672929df2f00828c1bbdc7cbcb2fc690eab4e73efde6be9104584ba7b6944853861f6d05e775b124ce8dfd5

## Release Comment

Many committers, developers, and users who provided bug reports helped
us to make this release.
Thanks for their contributions.