Arbitrary heap exposure during a JSON.generate callRuby through 2.2.7, 2.3.x through 2.3.4, and 2.4.x through 2.4.1 can expose arbitrary memory during a JSON.generate call. The issues lies in using strdup in ext/json/ext/generator/generator.c, which will stop after encountering a #039;\\0#039; byte, returning a pointer to a string of length zero, which is not the length stored in space_len. Escape sequence injection vulnerability in the Basic authentication of WEBrickThe Basic authentication code in WEBrick library in Ruby before 2.2.8, 2.3.x before 2.3.5, and 2.4.x through 2.4.1 allows remote attackers to inject terminal emulator escape sequences into its log and possibly execute arbitrary commands via a crafted user name. Buffer underrun in OpenSSL ASN1 decodeThe decode method in the OpenSSL::ASN1 module in Ruby before 2.2.8, 2.3.x before 2.3.5, and 2.4.x through 2.4.1 allows attackers to cause a denial of service via a crafted string. No size limit in summary length of gem specRubyGems version 2.6.12 and earlier is vulnerable to maliciously crafted gem specifications to cause a denial of service attack against RubyGems clients who have issued a `query` command. Arbitrary file overwrite due to incorrect validation of specification nameRubyGems version 2.6.12 and earlier fails to validate specification names, allowing a maliciously crafted gem to potentially overwrite any file on the filesystem. DNS hijacking vulnerabilityRubyGems version 2.6.12 and earlier is vulnerable to a DNS hijacking vulnerability that allows a MITM attacker to force the RubyGems client to download and install gems from a server that the attacker controls. Buffer underrun vulnerability in Kernel.sprintfRuby before 2.4.2, 2.3.5, and 2.2.8 is vulnerable to a malicious format string which contains a precious specifier with a huge minus value. Such situation can lead to a buffer overrun, resulting in a heap memory corruption or an information disclosure from the heap. Escape sequence in the "summary" field of gemspecRubyGems version 2.6.12 and earlier is vulnerable to maliciously crafted gem specifications that include terminal escape characters. Printing the gem specification would execute terminal escape sequences