CVE-2019-18978

Publication date 14 November 2019

Last updated 26 August 2025

Ubuntu priority

Cvss 3 Severity Score

Description

An issue was discovered in the rack-cors (aka Rack CORS Middleware) gem before 1.0.4 for Ruby. It allows ../ directory traversal to access private resources because resource matching does not ensure that pathnames are in a canonical format.

From the Ubuntu Security Team

It was discovered that rack-cors did not properly handle relative file paths. An attacker could use this vulnerability to access arbitrary files.

Status

Show unmaintained releases

Package	Ubuntu Release	Status
ruby-rack-cors	25.10 questing	Not affected
	25.04 plucky	Not affected
	24.10 oracular	Not affected
	24.04 LTS noble	Not affected
	23.10 mantic	Not affected
	23.04 lunar	Not affected
	22.10 kinetic	Not affected
	22.04 LTS jammy	Not affected
	21.10 impish	Not affected
	21.04 hirsute	Not affected
	20.10 groovy	Not affected
	20.04 LTS focal	Not affected
	19.10 eoan	Ignored end of life
	19.04 disco	Ignored end of life
	18.04 LTS bionic	Vulnerable
	16.04 LTS xenial	Fixed 0.4.0-1+deb9u2build0.16.04.1
	14.04 LTS trusty	Not in release

Patch details

For informational purposes only. We recommend not to cherry-pick updates. How can I get the fixes?

Package	Patch details
ruby-rack-cors	Upstream: e4d4fc3

Severity score breakdown

Parameter	Value
Base score	5.3 · Medium
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality	Low
Integrity impact	None
Availability impact	None
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

References

Related Ubuntu Security Notices (USN)

USN-4571-1
rack-cors vulnerability
5 October 2020