The Microsoft Office Online Server installation on the remote host is missing security updates. It is, therefore, affected by the following vulnerabilities:

  - Improper input validation in Microsoft Office Excel allows an unauthorized attacker to disclose     information locally. (CVE-2026-21258)

  - Heap-based buffer overflow in Microsoft Office Excel allows an unauthorized attacker to elevate privileges     locally. (CVE-2026-21259)

  - Out-of-bounds read in Microsoft Office Excel allows an unauthorized attacker to disclose information     locally. (CVE-2026-21261)

Detections

Analytics

Security Updates for Microsoft Office Online Server (February 2026)

high Nessus Plugin ID 298564

Version 1.1