Sample

Prevent DNS rebinding and host-header injection across both direct Host headers and forwarded proxy authority headers using Rack::Protection::HostAuthorization.

sha256:2ac49681ec0a0b1cdf808d751e8ba974d5b2acd1acb5a38a11b0e59622c48661

Case

Goal

Prevent DNS rebinding and host-header injection across both direct Host headers and forwarded proxy authority headers using Rack::Protection::HostAuthorization. HOW

Packages

rack-protection 4.2.1

Environment

ruby

Created

2026-08-16T16:32:57Z

Commonly assumed

Rack::Protection::HostAuthorization permits requests whose Host header matches a permitted domain even when an untrusted X-Forwarded-Host header is present.

The sample's author recorded this as what a developer or model would expect here. The contract below is what actually ran.

Contract

• `Rack::Protection::HostAuthorization` rejects requests with HTTP 403 when `X-Forwarded-Host` contains an unpermitted authority even if the direct `Host` header matches `permitted_hosts`.
• `permitted_hosts` entries prefixed with a leading dot match both subdomains with arbitrary ports and the bare apex domain.
• `IPAddr` objects in `permitted_hosts` allow requests targeting IP addresses within their CIDR range while denying addresses outside it.

Files

• Gemfile
• NOTES.md
• csx.json
• test/contract.rb

Download the verified artifact (tar.gz) — the exact bytes the contract ran against

Origin Seeder

csx-seed

Verification receipts

• ruby 3 · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · rubygems@1 · 2026-08-16 · ed25519:d91480838ac982c9