Various methods in WEBrick::HTTPRequest in Ruby 1.9.2 and 1.8.7 and earlier do not validate the X-Forwarded-For, X-Forwarded-Host and X-Forwarded-Server headers in requests, which might allow remote attackers to inject arbitrary text into log files or bypass intended address parsing via a crafted header.

Algorithmic complexity vulnerability in Gem::Version::VERSION_PATTERN in lib/rubygems/version.rb in RubyGems before 1.8.23.1, 1.8.24 through 1.8.25, 2.0.x before 2.0.8, and 2.1.x before 2.1.0, as used in Ruby 1.9.0 through 2.0.0p247, allows remote attackers to cause a denial of service (CPU consumption) via a crafted gem version that triggers a large amount of backtracking in a regular expression.

Algorithmic complexity vulnerability in Gem::Version::ANCHORED_VERSION_PATTERN in lib/rubygems/version.rb in RubyGems before 1.8.23.2, 1.8.24 through 1.8.26, 2.0.x before 2.0.10, and 2.1.x before 2.1.5, as used in Ruby 1.9.0 through 2.0.0p247, allows remote attackers to cause a denial of service (CPU consumption) via a crafted gem version that triggers a large amount of backtracking in a regular expression. NOTE: this issue is due to an incomplete fix for CVE-2013-4287.

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.

The safe-level feature in Ruby 1.8.7 allows context-dependent attackers to modify strings via the NameError#to_s method when operating on Ruby objects. NOTE: this issue is due to an incomplete fix for CVE-2011-1005.

Ruby 1.8.7 before patchlevel 371, 1.9.3 before patchlevel 286, and 2.0 before revision r37068 allows context-dependent attackers to bypass safe-level restrictions and modify untainted strings via the name_err_mesg_to_str API function, which marks the string as tainted, a different vulnerability than CVE-2011-1005.

GRScript18.dll before 1.2.2.0 in ActiveScriptRuby (ASR) before 1.8.7 does not properly restrict interaction with an Internet Explorer ActiveX environment, which allows remote attackers to execute arbitrary Ruby code via a crafted HTML document.

Ruby (aka CRuby) before 1.8.7-p357 computes hash values without 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.

The SecureRandom.random_bytes function in lib/securerandom.rb in Ruby before 1.8.7-p352 and 1.9.x before 1.9.2-p290 relies on PID values for initialization, which makes it easier for context-dependent attackers to predict the result string by leveraging knowledge of random strings obtained in an earlier process with the same PID.

Ruby before 1.8.7-p352 does not reset the random seed upon forking, which makes it easier for context-dependent attackers to predict the values of random numbers by leveraging knowledge of the number sequence obtained in a different child process, a related issue to CVE-2003-0900. NOTE: this issue exists because of a regression during Ruby 1.8.6 development.