Ruby (aka CRuby) 1.9 before 1.9.3-p327 and 2.0 before r37575 computes hash values without properly restricting the ability to trigger hash collisions predictably, which allows context-dependent attackers to cause a denial of service (CPU consumption) via crafted input to an application that maintains a hash table, as demonstrated by a universal multicollision attack against a variant of the MurmurHash2 algorithm, a different vulnerability than CVE-2011-4815.

Untrusted search path vulnerability in the installation functionality in Ruby 1.9.3-p194, when installed in the top-level C:\ directory, might allow local users to gain privileges via a Trojan horse DLL in the C:\Ruby193\bin directory, which may be added to the PATH system environment variable by an administrator, as demonstrated by a Trojan horse wlbsctrl.dll file used by the "IKE and AuthIP IPsec Keying Modules" system service in Windows Vista SP1, Windows Server 2008 SP2, Windows 7 SP1, and Windows 8 Release Preview. NOTE: CVE disputes this issue because the unsafe PATH is established only by a separate administrative action that is not a default part of the Ruby installation

The OpenSSL::SSL.verify_certificate_identity function in lib/openssl/ssl.rb in Ruby 1.8 before 1.8.7-p374, 1.9 before 1.9.3-p448, and 2.0 before 2.0.0-p247 does not properly handle a '\0' character in a domain name in the Subject Alternative Name field of an X.509 certificate, which allows man-in-the-middle attackers to spoof arbitrary SSL servers via a crafted certificate issued by a legitimate Certification Authority, a related issue to CVE-2009-2408.