What is CVE-2026-26144?

CVE-2026-26144 is a high-severity vulnerability in Microsoft 365 Apps, classified under Cross-site Scripting. CVSS score: 7.5/10. Published 2026-03-10.

How severe is CVE-2026-26144?

High severity. CVSS v3 base score is 7.5 out of 10.

XSS in Microsoft 365 Apps

CVE-2026-26144

Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Office Excel allows an unauthorized attacker to disclose information over a network.

Vulnerability class: XSS (Cross-Site Scripting)

Published 2026-03-10 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.

EPSS exploit prediction

EPSS: 0.008 (53.9th percentile), scored 2026-09-29.

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 54th percentile — 53.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.012 · newest: 0.008 · change: -0.004

Affected products

Microsoft 365 Apps
Microsoft 365 Apps For Enterprise — versions 16.0.1

Weakness classification (CWE)

CWE-79 — Cross-site Scripting

References

msrc.microsoft.com/update-guide/vulnerability/CVE-2026-26144 (vendor-advisory, patch, Vendor Advisory)

Frequently asked questions

What is CVE-2026-26144?: CVE-2026-26144 is a high-severity vulnerability in Microsoft 365 Apps, classified under Cross-site Scripting. CVSS score: 7.5/10. Published 2026-03-10.
How severe is CVE-2026-26144?: High severity. CVSS v3 base score is 7.5 out of 10.