USN-5253-1

It was discovered that Rack insecurely handled session ids. An unauthenticated remote attacker could possibly use this issue to perform a timing attack and hijack sessions. (CVE-2019-16782)

It was discovered that Rack was incorrectly handling cookies during parsing, not validating them or performing the necessary integrity checks. An attacker could possibly use this issue to overwrite existing cookie data and gain control over a remote system's behaviour. This issue only affected Ubuntu 14.04 ESM. (CVE-2020-8184)

It was discovered that Rack was not properly parsing data when processing multipart POST requests. If a user or automated system were tricked into sending a specially crafted multipart POST request to an application using Rack, a remote attacker could possibly use this issue to cause a denial of service. This issue was only fixed in Ubuntu 14.04 ESM and Ubuntu 16.04 ESM. (CVE-2022-30122)

It was discovered that Rack was not properly escaping untrusted data when performing logging operations, which could cause shell escaped sequences to be written to a terminal. If a user or automated system were tricked into sending a specially crafted request to an application using Rack, a remote attacker could possibly use this issue to execute arbitrary code in the machine running the application. This issue was only fixed in Ubuntu 14.04 ESM and Ubuntu 16.04 ESM. (CVE-2022-30123)