{"abstract":"Proxy bypass cidr matches address network membership.","category":"Proxy forwarding","checks":4,"contract":"Bounded offline decision model: proxy bypass cidr matches address network membership. Inputs are already validated protocol fields; the explicit fixtures define the supported policy, not a complete protocol implementation.","evaluation_group":"xh-proxy-bypass-cidr-matches-address-network-membership","failed_approach":"The attempted repair uses `address.startswith(network.split(\"/\")[0].rsplit(\".\",1)[0])` and still violates a separate fixture.","family":"xh-proxy-bypass-cidr-matches-address-network-membership","id":"FA-7061","implementations":{"attempt":{"sha256":"5d8835562d52b7a3873716974d1b672f55599d9c20717dcb9288d2e1b509fe79","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport ipaddress\nimport re\nfrom urllib.parse import urlsplit, urljoin\nN = 1\nobservations = []\ndef solve(address, network):\n    return address.startswith(network.split(\"/\")[0].rsplit(\".\",1)[0])\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve('10.1.2.3', '10.0.0.0/8'), True)\", \"check('fixture 2', solve('10.0.0.200', '10.0.0.0/25'), False)\", \"check('fixture 3', solve('192.0.2.1', '10.0.0.0/8'), False)\", \"check('fixture 4', solve('10.0.0.0', '10.0.0.0/8'), True)\"]\nfor _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:\n    exec(_line)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"broken":{"sha256":"c70815eb520e98596c912f4e42601c9c9291f7b497a645e76478c070ac2e7aa2","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport ipaddress\nimport re\nfrom urllib.parse import urlsplit, urljoin\nN = 1\nobservations = []\ndef solve(address, network):\n    return address == network.split(\"/\")[0]\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve('10.1.2.3', '10.0.0.0/8'), True)\", \"check('fixture 2', solve('10.0.0.200', '10.0.0.0/25'), False)\", \"check('fixture 3', solve('192.0.2.1', '10.0.0.0/8'), False)\", \"check('fixture 4', solve('10.0.0.0', '10.0.0.0/8'), True)\"]\nfor _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:\n    exec(_line)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"},"fixed":{"sha256":"34ba0753541b8761625907c9b7feffd8e79c54085c0ebfa9e9db46a38be94e3b","source":"\"\"\"Failure Map reference implementation. Python standard library only.\"\"\"\nimport json\nimport ipaddress\nimport re\nfrom urllib.parse import urlsplit, urljoin\nN = 1\nobservations = []\ndef solve(address, network):\n    return ipaddress.ip_address(address) in ipaddress.ip_network(network)\ndef check(label, actual, expected):\n    observations.append({\"check\": label, \"actual\": actual, \"expected\": expected, \"passed\": actual == expected})\n_fixtures = [\"check('fixture 1', solve('10.1.2.3', '10.0.0.0/8'), True)\", \"check('fixture 2', solve('10.0.0.200', '10.0.0.0/25'), False)\", \"check('fixture 3', solve('192.0.2.1', '10.0.0.0/8'), False)\", \"check('fixture 4', solve('10.0.0.0', '10.0.0.0/8'), True)\"]\nfor _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:\n    exec(_line)\nprint(json.dumps({\"observations\": observations, \"passed\": all(x[\"passed\"] for x in observations)}, ensure_ascii=False))\nraise SystemExit(0 if all(x[\"passed\"] for x in observations) else 1)\n"}},"limitations":"Bounded deterministic policy model over validated inputs; not a complete protocol stack or an interoperability claim. The five variants rotate the same explicit fixture set. This reproducer isolates one failure mechanism. Results cover the supplied fixtures. Variants within a family share a test contract and should remain grouped when constructing evaluation splits. Related mechanisms with a shared evaluation_group must also remain together; these controlled models are not independent production incidents.","method":"Deterministic executable model with adversarial boundary fixtures.","provenance":{"created_by":"Failure Map","dependencies":"Python standard library","family":"xh-proxy-bypass-cidr-matches-address-network-membership","generated_at":"2026-09-29T14:38:07.911403+00:00","license":"CC0-1.0","python":"3.12.14","seed":1,"split":"open-access"},"relevance":"This deterministic proxy forwarding model isolates the proxy-bypass-cidr-matches-address-network-membership policy at a network component boundary.","repair":"Apply the explicit proxy-bypass-cidr-matches-address-network-membership contract, including the tested boundary and negative cases.","root_cause":"The faulty implementation uses `address == network.split(\"/\")[0]` for the proxy-bypass-cidr-matches-address-network-membership decision.","sha256":"89dfa9beaad6da2164a37503c4b4e9c27ccfe3f899582def82e9ef0b3f787112","title":"Proxy bypass cidr matches address network membership · case 01","variant":1,"variant_policy":"Five numbered records share a model and may reuse boundary fixtures.","verification":{"attempt":{"elapsed_ms":36.398,"exit_code":1,"observations":[{"actual":true,"check":"fixture 2","expected":false,"passed":false},{"actual":false,"check":"fixture 3","expected":false,"passed":true},{"actual":true,"check":"fixture 4","expected":true,"passed":true},{"actual":false,"check":"fixture 1","expected":true,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": true, \"expected\": false, \"passed\": false}, {\"check\": \"fixture 3\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": true, \"expected\": true, \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": false, \"expected\": true, \"passed\": false}], \"passed\": false}\n"},"broken":{"elapsed_ms":36.096,"exit_code":1,"observations":[{"actual":false,"check":"fixture 2","expected":false,"passed":true},{"actual":false,"check":"fixture 3","expected":false,"passed":true},{"actual":true,"check":"fixture 4","expected":true,"passed":true},{"actual":false,"check":"fixture 1","expected":true,"passed":false}],"passed":false,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": true, \"expected\": true, \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": false, \"expected\": true, \"passed\": false}], \"passed\": false}\n"},"fixed":{"elapsed_ms":34.797,"exit_code":0,"observations":[{"actual":false,"check":"fixture 2","expected":false,"passed":true},{"actual":false,"check":"fixture 3","expected":false,"passed":true},{"actual":true,"check":"fixture 4","expected":true,"passed":true},{"actual":true,"check":"fixture 1","expected":true,"passed":true}],"passed":true,"stderr":"","stdout":"{\"observations\": [{\"check\": \"fixture 2\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"fixture 3\", \"actual\": false, \"expected\": false, \"passed\": true}, {\"check\": \"fixture 4\", \"actual\": true, \"expected\": true, \"passed\": true}, {\"check\": \"fixture 1\", \"actual\": true, \"expected\": true, \"passed\": true}], \"passed\": true}\n"}},"verified":true,"visibility":"public"}