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Vulnerability record · CVE-2026-34785 · published 2 April 2026

CVE-2026-34785: Rack information exposure vulnerability

Rack · Rack

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.

7.5 CVSS 3.1 High EPSS 0.52% · top 58.4% CWE-187 · CWE-187CWE-200 · Information exposure
7.5CVSS 3.1 base score
0.52%EPSS exploitation probability, 30 days
NoNot in CISA KEV
1Affected product versions listed by NVD
4References
24 Jul 2026Last modified by NVD

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.

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

Affected products

1 vulnerable configurations from NVD's CPE data, grouped by vendor and product.

References

LinkTags
https://github.com/rack/rack/security/advisories/GHSA-h2jq-g4cq-5ppq Vendor Advisory
https://access.redhat.com/security/cve/CVE-2026-34785
https://bugzilla.redhat.com/show_bug.cgi?id=2454486
https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-34785.json

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Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

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Source: NIST National Vulnerability Database (record CVE-2026-34785), CISA KEV, FIRST EPSS (scores of 2026-09-26). This page is refreshed as NVD updates the record.