PT-2026-29813 · Rack+3 · Rack+3

Haruki0409 · Published 2026-04-02 · Updated 2026-05-13 · CVE-2026-34786

Positive Technologies (AI Summary)

CVSS v3.1

5.3

Medium

Base vector

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

Name of the Vulnerable Software and Affected Versions Rack versions prior to 2.2.23, 3.1.21, and 3.2.6

Description Rack’s Rack::Static#applicable rules component evaluates header rules against the raw URL-encoded PATH INFO, while the file-serving path is decoded. This allows an attacker to bypass header rules by requesting an encoded form of a static path, potentially disabling security-relevant response headers. The issue arises from a canonicalization mismatch between the path used for header policy decisions and the path used for file serving. The impact depends on the configured rules and the types of files served.

Recommendations Update to Rack version 2.2.23, 3.1.21, or 3.2.6 or later.

Exploit

Fix

Weakness Enumeration

CWE-180

Related Identifiers

BDU:2026-07731

CVE-2026-34786

GHSA-Q4QF-9J86-F5MH

OPENSUSE-SU-2026:10508-1

USN-8182-1

Affected Products

Linuxmint

Rack

Red Os

Ubuntu

References · 39

• 🔥 https://github.com/rubysec/ruby-advisory-db/blob/master/gems/rack/CVE-2026-34786.yml · Exploit
• https://github.com/rack/rack/security/advisories/GHSA-q4qf-9j86-f5mh · Vendor Advisory
• https://ubuntu.com/security/CVE-2026-34830 · Vendor Advisory
• https://cve.org/CVERecord?id=CVE-2026-34786 · Security Note
• https://security-tracker.debian.org/tracker/CVE-2026-34786 · Vendor Advisory
• https://ubuntu.com/security/CVE-2026-34829 · Vendor Advisory
• https://ubuntu.com/security/notices/USN-8182-1 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-34786 · Security Note
• https://ubuntu.com/security/CVE-2026-34835 · Vendor Advisory
• https://osv.dev/vulnerability/DEBIAN-CVE-2026-34786 · Vendor Advisory
• https://osv.dev/vulnerability/openSUSE-SU-2026:10508-1 · Vendor Advisory
• https://osv.dev/vulnerability/GHSA-q4qf-9j86-f5mh · Vendor Advisory
• https://ubuntu.com/security/CVE-2026-34785 · Vendor Advisory
• https://osv.dev/vulnerability/USN-8182-1 · Vendor Advisory
• https://ubuntu.com/security/CVE-2026-34826 · Vendor Advisory