The Airbrake Ruby notifier 4.2.3 for Airbrake mishandles the blacklist_keys configuration option and consequently may disclose passwords to unauthorized actors. This is fixed in 4.2.4 (also, 4.2.2 and earlier are unaffected).

A TLS certificate validation flaw was found in Elastic APM agent for Ruby versions before 2.9.0. When specifying a trusted server CA certificate via the 'server_ca_cert' setting, the Ruby agent would not properly verify the certificate returned by the APM server. This could result in a man in the middle style attack against the Ruby agent.

WEBrick::HTTPAuth::DigestAuth in Ruby through 2.4.7, 2.5.x through 2.5.6, and 2.6.x through 2.6.4 has a regular expression Denial of Service cause by looping/backtracking. A victim must expose a WEBrick server that uses DigestAuth to the Internet or a untrusted network.

Ruby through 2.4.7, 2.5.x through 2.5.6, and 2.6.x through 2.6.4 allows code injection if the first argument (aka the "command" argument) to Shell#[] or Shell#test in lib/shell.rb is untrusted data. An attacker can exploit this to call an arbitrary Ruby method.

An issue was discovered in RubyGems 2.6 and later through 3.0.2. Gem::GemcutterUtilities#with_response may output the API response to stdout as it is. Therefore, if the API side modifies the response, escape sequence injection may occur.

An issue was discovered in RubyGems 2.6 and later through 3.0.2. Since Gem::UserInteraction#verbose calls say without escaping, escape sequence injection is possible.

An issue was discovered in RubyGems 2.6 and later through 3.0.2. The gem owner command outputs the contents of the API response directly to stdout. Therefore, if the response is crafted, escape sequence injection may occur.

An issue was discovered in RubyGems 2.6 and later through 3.0.2. A crafted gem with a multi-line name is not handled correctly. Therefore, an attacker could inject arbitrary code to the stub line of gemspec, which is eval-ed by code in ensure_loadable_spec during the preinstall check.

An issue was discovered in RubyGems 2.6 and later through 3.0.2. Since Gem::CommandManager#run calls alert_error without escaping, escape sequence injection is possible. (There are many ways to cause an error.)

Ruby OpenID (aka ruby-openid) through 2.8.0 has a remotely exploitable flaw. This library is used by Rails web applications to integrate with OpenID Providers. Severity can range from medium to critical, depending on how a web application developer chose to employ the ruby-openid library. Developers who based their OpenID integration heavily on the "example app" provided by the project are at highest risk.