RubyGems 2.0.x before 2.0.16, 2.2.x before 2.2.4, and 2.4.x before 2.4.7 does not validate the hostname when fetching gems or making API requests, which allows remote attackers to redirect requests to arbitrary domains via a crafted DNS SRV record, aka a "DNS hijack attack."

Heap-based buffer overflow in Ruby 1.8, 1.9 before 1.9.3-p484, 2.0 before 2.0.0-p353, 2.1 before 2.1.0 preview2, and trunk before revision 43780 allows context-dependent attackers to cause a denial of service (segmentation fault) and possibly execute arbitrary code via a string that is converted to a floating point value, as demonstrated using (1) the to_f method or (2) JSON.parse.

(1) DL and (2) Fiddle in Ruby 1.9 before 1.9.3 patchlevel 426, and 2.0 before 2.0.0 patchlevel 195, do not perform taint checking for native functions, which allows context-dependent attackers to bypass intended $SAFE level restrictions.

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.

lib/rexml/text.rb in the REXML parser in Ruby before 1.9.3-p392 allows remote attackers to cause a denial of service (memory consumption and crash) via crafted text nodes in an XML document, aka an XML Entity Expansion (XEE) attack.

darkfish.js in RDoc 2.3.0 through 3.12 and 4.x before 4.0.0.preview2.1, as used in Ruby, does not properly generate documents, which allows remote attackers to conduct cross-site scripting (XSS) attacks via a crafted URL.

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.

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.

The VpMemAlloc function in bigdecimal.c in the BigDecimal class in Ruby 1.9.2-p136 and earlier, as used on Apple Mac OS X before 10.6.7 and other platforms, does not properly allocate memory, which allows context-dependent attackers to execute arbitrary code or cause a denial of service (application crash) via vectors involving creation of a large BigDecimal value within a 64-bit process, related to an "integer truncation issue."