CVE-2026-34835 (GCVE-0-2026-34835)
Vulnerability from cvelistv5
Published
2026-04-02 17:09
Modified
2026-04-02 17:44
CWE
  • CWE-1286 - Improper Validation of Syntactic Correctness of Input
Summary
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.
Impacted products
Vendor Product Version
rack rack Version: >= 3.0.0.beta1, < 3.1.21
Version: >= 3.2.0, < 3.2.6
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Show details on NVD website


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