PT-2026-29813 · Rack · Rack

Haruki0409 · Published 2026-04-02 · Updated 2026-04-02 · CVE-2026-34786

Mitre

CVSS v3.1

5.3

Medium

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

Rack is a modular Ruby web server interface. Prior to versions 2.2.23, 3.1.21, and 3.2.6, Rack::Static#applicable rules evaluates several header rules types against the raw URL-encoded PATH INFO, while the underlying file-serving path is decoded before the file is served. As a result, a request for a URL-encoded variant of a static path can serve the same file without the headers that header rules were intended to apply. In deployments that rely on Rack::Static to attach security-relevant response headers to static content, this can allow an attacker to bypass those headers by requesting an encoded form of the path. This issue has been patched in versions 2.2.23, 3.1.21, and 3.2.6.

Fix

Weakness Enumeration

CWE-180

Related Identifiers

CVE-2026-34786

Affected Products

Rack

References · 2

• https://nvd.nist.gov/vuln/detail/CVE-2026-34786 · Security Note
• https://github.com/rack/rack/security/advisories/GHSA-q4qf-9j86-f5mh · Note