Three of the four flaws CISA added to its Known Exploited Vulnerabilities catalog on 24 April involve the same underlying weakness: path traversal. SimpleHelp, Samsung MagicINFO, and D-Link routers are all in the firing line. If you’ve seen “path traversal” or “directory traversal” in the headlines and skimmed past it, here’s what it actually means — and why it keeps showing up.

Think of a web application as a building with a front desk. You walk up, ask for the menu, and the receptionist hands you a copy. A path traversal bug is what happens when you ask for “the menu, but actually take me three floors up to the safe in the manager’s office” — and the receptionist just hands it over without checking. Attackers slip characters like ../../ into a file path the application uses, and the application obediently walks up its own directory tree to fetch files it should never expose: configuration files, credentials, private keys, or system files.

It matters right now because path traversal pairs ugly with other bugs. On its own it leaks data. Combined with a file-upload weakness — like the SimpleHelp chain — it becomes remote code execution and a foothold for ransomware. The Australian Cyber Security Centre’s advisory feed regularly flags this bug class because it sits inside almost any product that handles file uploads, content management, or remote administration.

The practical implication for your business: when an internet-facing system runs unpatched, “low-severity” file-read bugs aren’t really low-severity. Ask your IT provider how often the platforms behind your customer portals, document stores, and remote access tools are patched, and whether internet-exposed admin interfaces are restricted by IP or behind a VPN. Those two controls take most path traversal risk off the table.

If you want a clearer view of which of your business systems are exposed to the internet — and what’s actually running on them — All IT Services can run an external attack surface review and walk you through what to fix first.