CVE-2026-34785

Publication date 2 April 2026

Last updated 23 April 2026

Ubuntu priority

Cvss 3 Severity Score

Description

Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Static determines whether a request should be served as a static file using a simple string prefix check. When configured with URL prefixes such as "/css", it matches any request path that begins with that string, including unrelated paths such as "/css-config.env" or "/css-backup.sql". As a result, files under the static root whose names merely share the configured prefix may be served unintentionally, leading to information disclosure. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.

Status

Show unmaintained releases

Package	Ubuntu Release	Status
ruby-rack	25.10 questing	Fixed 3.1.16-0.1ubuntu0.3
	24.04 LTS noble	Fixed 2.2.7-1ubuntu0.7
	22.04 LTS jammy	Fixed 2.1.4-5ubuntu1.2+esm3
	20.04 LTS focal	Fixed 2.0.7-2ubuntu0.1+esm10
	18.04 LTS bionic	Fixed 1.6.4-4ubuntu0.2+esm10
	16.04 LTS xenial	Fixed 1.6.4-3ubuntu0.2+esm10
	14.04 LTS trusty	Fixed 1.5.2-3+deb8u3ubuntu1~esm11

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Patch details

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

Package	Patch details
ruby-rack	Upstream: 7a8f326

Severity score breakdown

Parameter	Value
Base score	7.5 · High
Attack vector	Network
Attack complexity	Low
Privileges required	None
User interaction	None
Scope	Unchanged
Confidentiality	High
Integrity impact	None
Availability impact	None
Vector	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

References

Related Ubuntu Security Notices (USN)

USN-8182-1
Rack vulnerabilities
17 April 2026