CVE-2026-55123

Think of this like a “gap” in PowerPoint’s ability to safely handle a particular kind of file. If someone sends you a specially crafted PowerPoint and you open it, that file can cause PowerPoint to misbehave and let an attacker run code on your computer. This is the kind of weakness attackers commonly use as a starting point for broader malware.

This matters to you if you use Microsoft PowerPoint as part of microsoft 365 apps, microsoft office, Microsoft Office 365 for Mac, Microsoft Office LTSC for Mac 2021, Microsoft Office LTSC for Mac 2024, or Microsoft PowerPoint 2016.
Because it requires user interaction (opening a crafted file) and does not require authentication, it can target everyday users through email or other file-sharing—especially if the attacker can reach your users.
Since “reachable in default config” is unknown and specific preconditions aren’t listed, treat it as a real risk anytime your systems can receive and open PowerPoint files from untrusted sources.

Mark this as urgent because a user-opening action can directly lead to arbitrary code running on the device (local execution) for affected PowerPoint editions. Even though public exploit code isn’t on record and KEV (CISA’s known-exploited list) isn’t present, the business risk remains high: opening a malicious attachment is enough.
With a RED verdict assigned, prioritize patching immediately across all affected Office/PowerPoint installations, then tighten file-handling until updates are verified.