CVE-2019-16254

Name of the Vulnerable Software and Affected Versions Ruby versions prior to 2.4.8 Ruby versions 2.5.x through 2.5.6 Ruby versions 2.6.x through 2.6.4 Puma versions prior to 3.12.3 Puma versions prior to 4.3.2

Description The issue is related to incorrect handling of special elements in the WEBrick library of the Ruby programming language interpreter. This can allow a remote attacker to perform cross-site scripting attacks by splitting HTTP responses. 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. The vulnerability is known as HTTP Response Splitting and can be used as a vector for other attacks, such as cross-site scripting (XSS).

Recommendations For Ruby versions prior to 2.4.8, update to version 2.4.8 or later to resolve the issue. For Ruby versions 2.5.x through 2.5.6, update to version 2.5.7 or later to resolve the issue. For Ruby versions 2.6.x through 2.6.4, update to version 2.6.5 or later to resolve the issue. For Puma versions prior to 3.12.3, update to version 3.12.3 or later to resolve the issue. For Puma versions prior to 4.3.2, update to version 4.3.2 or later to resolve the issue. As a temporary workaround, consider restricting the use of untrusted input in response headers until a patch is available. Avoid using newline characters (i.e., CR, LF, /r, /n) in headers to minimize the risk of exploitation.