FA-7691 / WebSocket and browser transport policies / Open access

Cors exposed header wildcard is literal with credentials · case 01

Cors exposed header wildcard is literal with credentials.

Verified by executionVariant 1 · 4 checks per implementationDownload source bundle ↓JSON ↗

ROOT CAUSE

The faulty implementation uses `header in exposed or "*" in exposed` for the cors-exposed-header-wildcard-is-literal-with-credentials decision.

VERIFIED REPAIR

Apply the explicit cors-exposed-header-wildcard-is-literal-with-credentials contract, including the tested boundary and negative cases.

Unsuccessful approach: The attempted repair uses `header in exposed` and still violates a separate fixture.

Case contract

Bounded offline decision model: cors exposed header wildcard is literal with credentials. Inputs are already validated protocol fields; the explicit fixtures define the supported policy, not a complete protocol implementation.

Why this case matters

This deterministic websocket and browser transport policies model isolates the cors-exposed-header-wildcard-is-literal-with-credentials policy at a network component boundary.

1 / The failure

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import ipaddress
import re
from urllib.parse import urlsplit, urljoin
N = 1
observations = []
def solve(header, exposed, credentials):
    return header in exposed or "*" in exposed
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve('x', ['*'], True), False)", "check('fixture 2', solve('x', ['*'], False), True)", "check('fixture 3', solve('X', ['x'], True), True)", "check('fixture 4', solve('x', [], False), False)"]
for _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:
    exec(_line)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
fixture 2	`True`	`True`	Passed
fixture 3	`False`	`True`	Failed
fixture 4	`False`	`False`	Passed
fixture 1	`True`	`False`	Failed

SHA-256 / 6956661805c5d5ff460f15607fcfad82d2c681b9556f6b044141a929a06798ce

2 / The unsuccessful fix

Exit 1

"""Failure Map reference implementation. Python standard library only."""
import json
import ipaddress
import re
from urllib.parse import urlsplit, urljoin
N = 1
observations = []
def solve(header, exposed, credentials):
    return header in exposed
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve('x', ['*'], True), False)", "check('fixture 2', solve('x', ['*'], False), True)", "check('fixture 3', solve('X', ['x'], True), True)", "check('fixture 4', solve('x', [], False), False)"]
for _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:
    exec(_line)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
fixture 2	`False`	`True`	Failed
fixture 3	`False`	`True`	Failed
fixture 4	`False`	`False`	Passed
fixture 1	`False`	`False`	Passed

SHA-256 / 46a62fbfbf4765e4464b5272f3dceb2ec4c6b640ba6cb93ef5cb6a05858421d7

3 / The verified repair

Exit 0

"""Failure Map reference implementation. Python standard library only."""
import json
import ipaddress
import re
from urllib.parse import urlsplit, urljoin
N = 1
observations = []
def solve(header, exposed, credentials):
    return header.lower() in {x.lower() for x in exposed} or ("*" in exposed and not credentials)
def check(label, actual, expected):
    observations.append({"check": label, "actual": actual, "expected": expected, "passed": actual == expected})
_fixtures = ["check('fixture 1', solve('x', ['*'], True), False)", "check('fixture 2', solve('x', ['*'], False), True)", "check('fixture 3', solve('X', ['x'], True), True)", "check('fixture 4', solve('x', [], False), False)"]
for _line in _fixtures[N % len(_fixtures):] + _fixtures[:N % len(_fixtures)]:
    exec(_line)
print(json.dumps({"observations": observations, "passed": all(x["passed"] for x in observations)}, ensure_ascii=False))
raise SystemExit(0 if all(x["passed"] for x in observations) else 1)

Boundary fixture	Actual	Expected	Outcome
fixture 2	`True`	`True`	Passed
fixture 3	`True`	`True`	Passed
fixture 4	`False`	`False`	Passed
fixture 1	`False`	`False`	Passed

SHA-256 / 177fa9bc887f09c6972650a3d8e110c6f150bee0067ab6d7c31a57b3cc9e77a9

Verification & scope

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.

Observations recorded using Python 3.12.14 at 2026-09-29T14:38:14.275763+00:00.

Case digest / 58102d70b197ea42a0c39d29869c850c55afc1c4b3bbf18fb13956be5542f9e0