Exposure of Sensitive System Information to an Unauthorized Control Sphere in Office Online Server and Microsoft Office - CVE-2026-97740

Vulnerability details

The vulnerability allows a remote attacker to read portions of process memory.

The vulnerability exists due to exposure of sensitive system information to an unauthorized control sphere in Microsoft Office Excel when processing a malicious Office file. A remote attacker can send a malicious Office file to a user and convince them to open it to read portions of process memory.

The Preview Pane is not an attack vector.

Affected software

How to mitigate CVE-2026-97740

External References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2026-97740
• https://learn.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates

Related Security Bulletins

• Multiple vulnerabilities in Microsoft Office