There is a possible XSS vulnerability in Rack before 2.0.6 and 1.6.11.
Carefully crafted requests can impact the data returned by the `scheme`
method on `Rack::Request`. Applications that expect the scheme to be
limited to 'http' or 'https' and do not escape the return value could be
vulnerable to an XSS attack. Note that applications using the normal
escaping mechanisms provided by Rails may not impacted, but applications
that bypass the escaping mechanisms, or do not use them may be vulnerable.
Ubuntu 12.04 ESM (Precise Pangolin):DNE
Ubuntu 14.04 ESM (Trusty Tahr):needed
Ubuntu 16.04 LTS (Xenial Xerus):needed
Ubuntu 18.04 LTS (Bionic Beaver):needed
Ubuntu 18.10 (Cosmic Cuttlefish):ignored (reached end-of-life)
Ubuntu 19.04 (Disco Dingo):not-affected (2.0.6-3)
Ubuntu 19.10 (Eoan):not-affected (2.0.6-3)
More Information

Updated: 2019-07-18 17:32:18 UTC (commit 649f8c6455205380e35ed054e9ea734222c716bb)