Installing the Fix for an Exploited WordPress Flaw Can Expose Some Sites One Last Time

A patch is supposed to close the door. In this WordPress case, some sites may still be exposed during the update itself if an attacker hits the timing just right.

A repair that still uses the broken lock

Imagine replacing a bad front-door lock, but the installer has to open the door one last time with the old broken key. That is the basic problem here.

Some WordPress sites can still be attacked while they install the fix for an actively exploited flaw, according to Umut Bayram, the Picus Security researcher who found it.

The issue is not that the fix is fake or useless. It is that the update process itself reportedly unpacks the new files using the site's old, unpatched code. If an attacker lands their shot in that brief window, they may be able to run code on the server.

That is a nasty edge case.

Why the update window matters

For people outside security, patching usually sounds simple: install update, bug gone. Most of the time, that is close enough.

But software updates are still software. They have steps. Files get downloaded, unpacked, moved into place, and loaded by the application. If one of those steps still relies on the vulnerable part, then the system can stay exposed until the process fully finishes.

That appears to be the concern here.

The practical idea is straightforward. An attacker does not need the site to stay vulnerable forever. They just need one usable opening. If the old code handles the unpacking during the fix, then the patching moment itself can become one last chance to exploit the flaw.

Think of it like changing a tire while the car is still rolling slowly. You are on the way to safer conditions, but there is still a risky moment in the middle.

This is also a good reminder that “patched” and “safe right this second” are not always the same thing. Timing can matter, especially with flaws that are already under active attack.

The practical advice is simple: cut off web traffic first

Bayram's advice is to block web access to the site before installing the fix.

That makes sense. If the danger window depends on an attacker reaching the site at exactly the wrong time, removing public access during the update cuts off the easiest path.

For site owners and admins, the safest approach is the boring one:

• Put the site into a maintenance state or otherwise block public web access before starting the update.
• Apply the fix only after outside requests can no longer hit the vulnerable code path.
• Bring the site back online after the update is fully complete.
• Check logs and admin activity afterward for anything unusual, especially if the site stayed publicly reachable during the patch.

If you run a business site and cannot tolerate much downtime, this is still usually a short interruption compared with the mess of server-side code execution.

A few minutes offline beats a cleanup project.

What site owners should take from this

The notable part is not just the flaw itself. It is the update path. Security problems do not only live in the bug; they can also show up in the way the fix gets installed.

That is easy to miss because patching is treated as the safe step. Usually it is. But for actively exploited bugs, it is worth asking one extra question: do I need to isolate the system before I patch it?

For WordPress administrators, that means treating emergency updates a bit more like maintenance on live electrical wiring. Do the work, but cut the power first if you can.

If you manage sites for other people, this is also a process problem. Your runbook should not stop at “apply update.” It should include temporary access controls, a maintenance window, and a quick review afterward.

The clear lesson is simple: when a fix still depends on old vulnerable code during installation, the safest patch is an isolated patch. Block access first, then update, then reopen the site once the repair is done.