Microsoft Office OneNote Remote Code Execution Vulnerability
CVE-2026-126526
Summary
Improper neutralization of special elements used in a command ('command injection') in Microsoft 365 Copilot's Business Chat allows an unauthorized attacker to disclose information over a network.
Products covered
Microsoft 365 Copilot's Business Chat
Remediation
Separate remediation guidance was not included in the collected bulletin.
CVEs in this advisory 1
Update history
What changed in later vendor updates
SecurityAlert records field-level changes from the point we begin following a bulletin. Earlier vendor changes may not have a field-by-field record.
- CVSS changed from 7.4 to 8.6.
- The vendor changed the advisory's last-updated date.
Updates
- Published by Microsoft Security Response Center
The publication date reported by the vendor.
- Added to SecurityAlert
We collected the advisory from the official source.
- Updated by Microsoft Security Response Center
The vendor changed the advisory after it was first published.
- Confirmed at the source
Our collector saw this advisory during a later source check.