CISA: Microsoft SharePoint RCE flaw now actively exploited
Active SharePoint RCE exploit requires immediate, prioritized patching and validation.
The headline is the easy part. A CISA alert says a SharePoint RCE is being actively exploited, so you need to patch. The useful question is what this kind of fire drill exposes about how security programs actually work—or don’t.
What happened
CISA is warning that a high-severity remote code execution (RCE) vulnerability in Microsoft SharePoint is being actively exploited. Microsoft patched this flaw back in May. Because SharePoint is used everywhere for document management and internal sites, an active RCE is a serious problem. The risk is no longer theoretical; it’s happening now.
What people will get wrong
The common mistake is to see this as just another patching bulletin. It’s not. This is a pop quiz for your asset management, patching discipline, and response capability.
The real failure didn’t start today with the CISA alert. It started sometime between May, when the patch was first released, and now. Why wasn’t every SharePoint server patched then? What broke in the process? The headline is about the exploit, but the lesson is about the gap in coverage that the attackers just found. This is really an ownership problem.
Practitioner lens
For any practitioner, this alert means you drop what you’re doing. This isn’t a “wait for the next patch Tuesday” situation.
First, can you even produce a list of every SharePoint instance you’re responsible for, right now? If the answer is “maybe” or “I have to ask three teams,” that’s the real emergency. If nobody owns the asset, nobody owns the risk.
Second, verify the patch. Don’t just trust the dashboard in your vulnerability management tool. The dashboard is not the control. You need to confirm on the box or through an authenticated scan that the patch is actually installed. That sounds simple, but it’s where programs break—assuming a green checkmark equals a secured server.
Finally, you have to assume compromise and start hunting. The exploit is active, which means you’re not just patching to prevent a breach; you might be investigating one that’s already happened. Are you reviewing SharePoint access logs and network traffic for anomalous behavior? Can you even detect a new web shell or suspicious process running on those servers? If you don’t have that visibility, you can’t prove what happened.
What I would watch next
The interesting part isn’t what attackers do with this exploit tomorrow. It’s what your team does.
Did this fire drill expose unmanaged servers, gaps in your logging, or a broken patching process? The signal to watch is whether this alert leads to fixing those systemic issues. Or will everyone just move on when the story fades from the news feed, leaving the same gaps open for the next “emergency”?
Generated from Hermes Relay’s daily cyber briefing and edited through Tony’s practitioner voice profile before publishing to this blog.
Source: CISA: Microsoft SharePoint RCE flaw now actively exploited
Pipeline note: lens: The number that matters; draft model: projects/project-a89720ac-d6be-45fe-a4b/locations/us-central1/publishers/google/models/gemini-2.5-flash.