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

MITRE NVD CVE.ORG JSON API Print: PDF PDF

Summary

CVECVE-2026-34785
StatePUBLISHED
AssignerGitHub_M
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-04-02 17:16:24 UTC
Updated2026-06-30 03:18:58 UTC
DescriptionRack 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.

Risk And Classification

Primary CVSS: v3.1 7.5 HIGH from ADP

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

EPSS: 0.000430000 probability, percentile 0.130170000 (date 2026-04-21)

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

VersionSourceTypeScoreSeverityVector
3.1ADPCVSS7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
3.1[email protected]Secondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
3.10b0ca135-0b70-47e7-9f44-1890c2a1c46cSecondary7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
3.1CNADECLARED7.5HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Application Rack Rack All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Rack Rack affected < 2.2.23 Not specified
CNA Rack Rack affected >= 3.0.0.beta1, < 3.1.21 Not specified
CNA Rack Rack affected >= 3.2.0, < 3.2.6 Not specified
ADP Red Hat Red Hat Satellite 6 Not specified Not specified

References

ReferenceSourceLinkTags
security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-34785.json 0b0ca135-0b70-47e7-9f44-1890c2a1c46c security.access.redhat.com
bugzilla.redhat.com/show_bug.cgi 0b0ca135-0b70-47e7-9f44-1890c2a1c46c bugzilla.redhat.com
github.com/rack/rack/security/advisories/GHSA-h2jq-g4cq-5ppq [email protected] github.com Vendor Advisory
access.redhat.com/security/cve/CVE-2026-34785 0b0ca135-0b70-47e7-9f44-1890c2a1c46c access.redhat.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Additional Advisory Data

SourceTimeEvent
ADP2026-04-02T18:01:13.485ZReported to Red Hat.
ADP2026-04-02T16:44:17.134ZMade public.
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