Ruby through 2.4.7, 2.5.x through 2.5.6, and 2.6.x through 2.6.4 allows HTTP Response Splitting. If a program using WEBrick inserts untrusted input into the response header, an attacker can exploit it to insert a newline character to split a header, and inject malicious content to deceive clients. NOTE: this issue exists because of an incomplete fix for CVE-2017-17742, which addressed the CRLF vector, but did not address an isolated CR or an isolated LF.

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."

In Puma (RubyGem) before 4.3.2 and before 3.12.3, if an application using Puma allows untrusted input in a response header, an attacker can use newline characters (i.e. `CR`, `LF` or`/r`, `/n`) to end the header and inject malicious content, such as additional headers or an entirely new response body. This vulnerability is known as HTTP Response Splitting. While not an attack in itself, response splitting is a vector for several other attacks, such as cross-site scripting (XSS). This is related to CVE-2019-16254, which fixed this vulnerability for the WEBrick Ruby web server. This has been fixed in versions 4.3.2 and 3.12.3 by checking all headers for line endings and rejecting headers with those characters.

Ruby before 2.2.10, 2.3.x before 2.3.7, 2.4.x before 2.4.4, 2.5.x before 2.5.1, and 2.6.0-preview1 allows an HTTP Response Splitting attack. An attacker can inject a crafted key and value into an HTTP response for the HTTP server of WEBrick.

The JSON gem through 2.2.0 for Ruby, as used in Ruby 2.4 through 2.4.9, 2.5 through 2.5.7, and 2.6 through 2.6.5, has an Unsafe Object Creation Vulnerability. This is quite similar to CVE-2013-0269, but does not rely on poor garbage-collection behavior within Ruby. Specifically, use of JSON parsing methods can lead to creation of a malicious object within the interpreter, with adverse effects that are application-dependent.

CGI::Cookie.parse in Ruby through 2.6.8 mishandles security prefixes in cookie names. This also affects the CGI gem through 0.3.0 for Ruby.

The rb_get_path_check function in file.c in Ruby 1.9.3 before patchlevel 286 and Ruby 2.0.0 before r37163 allows context-dependent attackers to create files in unexpected locations or with unexpected names via a NUL byte in a file path.

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.

Ruby 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 (1) exc_to_s or (2) name_err_to_s API function, which marks the string as tainted, a different vulnerability than CVE-2012-4466. NOTE: this issue might exist because of a CVE-2011-1005 regression.

An issue was discovered in Ruby through 2.5.8, 2.6.x through 2.6.6, and 2.7.x through 2.7.1. WEBrick, a simple HTTP server bundled with Ruby, had not checked the transfer-encoding header value rigorously. An attacker may potentially exploit this issue to bypass a reverse proxy (which also has a poor header check), which may lead to an HTTP Request Smuggling attack.

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.

The (1) Net::ftptls, (2) Net::telnets, (3) Net::imap, (4) Net::pop, and (5) Net::smtp libraries in Ruby 1.8.5 and 1.8.6 do not verify that the commonName (CN) field in a server certificate matches the domain name in a request sent over SSL, which makes it easier for remote attackers to intercept SSL transmissions via a man-in-the-middle attack or spoofed web site, different components than CVE-2007-5162.

The REXML gem before 3.2.5 in Ruby before 2.6.7, 2.7.x before 2.7.3, and 3.x before 3.0.1 does not properly address XML round-trip issues. An incorrect document can be produced after parsing and serializing.

In Ruby before 2.2.10, 2.3.x before 2.3.7, 2.4.x before 2.4.4, 2.5.x before 2.5.1, and 2.6.0-preview1, the UNIXServer.open and UNIXSocket.open methods are not checked for null characters. It may be connected to an unintended socket.

Directory traversal vulnerability in the Dir.mktmpdir method in the tmpdir library in Ruby before 2.2.10, 2.3.x before 2.3.7, 2.4.x before 2.4.4, 2.5.x before 2.5.1, and 2.6.0-preview1 might allow attackers to create arbitrary directories or files via a .. (dot dot) in the prefix argument.

In Ruby through 3.0 on Windows, a remote attacker can submit a crafted path when a Web application handles a parameter with TmpDir.