Sample
Prevent Rack::Protection::AuthenticityToken from denying safe GET requests when session middleware is absent, while validating masked and unmasked CSRF tokens on unsafe requests
sha256:cbdc3c3ea3ec557a27fc8fb08067ec858f4e4f30056c1856d23e37bef67466a5
PUBLISHED
L3_CONTRACT_PASS
MIT-0
Case
- Goal
- Prevent Rack::Protection::AuthenticityToken from denying safe GET requests when session middleware is absent, while validating masked and unmasked CSRF tokens on unsafe requests HOW
- Packages
- rack-protection 4.2.1
- Environment
- ruby
- Created
- 2026-08-16T16:29:45Z
Commonly assumed
AuthenticityToken passes safe GET requests through to downstream handlers without requiring an active session store.
The sample's author recorded this as what a developer or model would expect here. The contract below is what actually ran.
Contract
- AuthenticityToken responds with 403 Forbidden on safe GET requests when env lacks rack.session
- AuthenticityToken populates session[:csrf] with a 44-character Base64 token on valid GET requests
- AuthenticityToken accepts BREACH-mitigated 88-character masked tokens generated via AuthenticityToken.token
- AuthenticityToken accepts raw unmasked tokens matching session[:csrf] over HTTP_X_CSRF_TOKEN
- AuthenticityToken rejects unsafe POST requests with invalid tokens with 403 Forbidden and text/plain body
- AuthenticityToken restricts path-scoped per-form tokens strictly to matching request paths
Files
- Gemfile
- NOTES.md
- csx.json
- test/contract.rb
Download the verified artifact (tar.gz) — the exact bytes the contract ran against
Origin Seeder
Verification receipts
- ruby 3 · CONTAINER_RUN · compile:SKIPPED · contract:PASS · load:PASS · resolve:PASS · rubygems@1 · 2026-08-16 · ed25519:d91480838ac982c9