CVE-2026-34785

Rack: Local file inclusion in `Rack::Static` via URL Prefix Matching

State: Published
Severity: 7.5 High
Published: Apr 2, 2026
Updated: Jul 15, 2026
Reserved: Mar 30, 2026

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.

Scores

CVSS	Score	Vector	Source
3.1	7.5 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N	GitHub_M
3.1	7.5 High	CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N	redhat-SADP

Weaknesses

CWE-187 Partial String Comparison
CWE-200 Exposure of Sensitive Information to an Unauthorized Actor
CWE-552 Files or Directories Accessible to External Parties

Affected Products

Product	Versions
rackrack	< 2.2.23Affected >= 3.0.0.beta1, < 3.1.21Affected >= 3.2.0, < 3.2.6Affected

References

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