Microsoft · Office · Microsoft Office Remote Code Execution
Verdict
Patch first · actively exploited, reachable from the internet without credentials, and in the top 5% of CVEs by near-term exploitation probability
Added to CISA KEV 2026-04-14 · exploited in the wild for 166 days
CVSS 8.8 HIGH. The score is a summary; these three components are the part that decides whether something scanning the internet can use it.
| Attack vector | networkreachable over the network, with no local access needed |
|---|---|
| Privileges required | noneneeds no credentials at all |
| User interaction | requiredneeds a user to click, load or submit something first |
| Base vector | CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H |
| Weakness | CWE-94 |
This describes the vulnerability. It says nothing about whether your systems run it.
EPSS puts the probability of exploitation in the next 30 days at 0.4321, which places it in the top 5% of all tracked CVEs. The percentile is the more useful half: 0.18 in absolute terms sounds low until you know most of the internet-facing software in the world scores under that.
| EPSS probability | 0.4321 |
|---|---|
| Percentile | 0.987 — top 5% |
| Added to KEV | 2026-04-14 |
|---|---|
| Days exploited | 166 |
| Federal remediation due | not set |
| Ransomware use | no known ransomware campaign use |
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Microsoft Office Excel 2000 SP3, 2002 SP3, 2003 SP3, and 2007 SP1; Excel Viewer 2003 Gold and SP3; Excel Viewer; Compatibility Pack for Word, Excel, and PowerPoint 2007 File Formats SP1; and Excel in Microsoft Office 2004 and 2008 for Mac allow remote attackers to execute arbitrary code via a crafted Excel document that triggers an access attempt on an invalid object, as exploited in the wild in February 2009 by Trojan.Mdropper.AC.