high7.5
CVE-2026-34785
Rack::Static prefix matching can expose unintended files under the static root
Impact
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.
Affected packages
| Ecosystem | Package | Affected | Fixed in |
|---|---|---|---|
| rubygems | rack | < 2.2.23 | 2.2.23 |
Affected products
| Vendor | Product | Affected versions |
|---|---|---|
| Rack | Rack | before 2.2.23 from 3.0.0 before 3.1.21 from 3.2.0 before 3.2.6 |
Weakness classification
References
- NVD record
- CVE.org record
- GitHub advisory
- https://github.com/advisories/GHSA-h2jq-g4cq-5ppq
- https://github.com/rack/rack/security/advisories/GHSA-h2jq-g4cq-5ppq
- https://nvd.nist.gov/vuln/detail/CVE-2026-34785
- https://github.com/rubysec/ruby-advisory-db/blob/master/gems/rack/CVE-2026-34785.yml
- 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