Improper Validation of Syntactic Correctness of Input Affecting ruby-rack package, versions *


Severity

Recommended
0.0
medium
0
10

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Threat Intelligence

EPSS
0.06% (20th percentile)

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  • Snyk IDSNYK-DEBIAN11-RUBYRACK-15922769
  • published7 Apr 2026
  • disclosed2 Apr 2026

Introduced: 2 Apr 2026

NewCVE-2026-34835  (opens in a new tab)
CWE-1286  (opens in a new tab)

How to fix?

There is no fixed version for Debian:11 ruby-rack.

NVD Description

Note: Versions mentioned in the description apply only to the upstream ruby-rack package and not the ruby-rack package as distributed by Debian. See How to fix? for Debian:11 relevant fixed versions and status.

Rack is a modular Ruby web server interface. From versions 3.0.0.beta1 to before 3.1.21, and 3.2.0 to before 3.2.6, Rack::Request parses the Host header using an AUTHORITY regular expression that accepts characters not permitted in RFC-compliant hostnames, including /, ?, #, and @. Because req.host returns the full parsed value, applications that validate hosts using naive prefix or suffix checks can be bypassed. This can lead to host header poisoning in applications that use req.host, req.url, or req.base_url for link generation, redirects, or origin validation. This issue has been patched in versions 3.1.21 and 3.2.6.

CVSS Base Scores

version 3.1