The filename 'loginCheckTest.php' is your first and most important indicator: this is test infrastructure that never should have reached production. The 'Test' suffix marks code written with an implicit expiration date — the developer assumed it would be deleted before deployment. That assumption is now permanently violated in every live copy of this software, which means you're not looking at a conventional security defect; you're looking at a deployment governance failure that likely brought other unintended artifacts along with it.
This changes your remediation posture. Standard patching advice doesn't apply here because there is no patch coming and no vendor response. What matters is identifying whether this file exists in your environment at all, and treating that discovery as a canary for a broader problem: if test scaffolding handling authentication logic made it to production, other debug files, admin utilities, and development artifacts probably did too. The absence of versioning in this project means you cannot rely on comparing release tags to determine if you're running a vulnerable copy — you're limited to file-system archaeology on live systems.
Your immediate actions: first, scan for loginCheckTest.php and any other file containing 'test', 'debug', 'admin', or 'util' in the name within your web-accessible directories. Second, audit authentication-adjacent code for raw SQL construction — if the test file used unsanitized SQL in auth logic, the same developer likely applied the same pattern elsewhere. Third, assume this codebase has no security gate and treat every finding as potentially representing a pattern rather than an isolated issue. The EPSS score of 0.00254 is reassuring short-term, but it measures current opportunistic scanning, not the risk of targeted reconnaissance against a known, unpatchable exposure in software that organizations may not even realize they're running.