Out-of-bounds read in Microsoft Office for macOS and Microsoft Office - CVE-2026-109501

Vulnerability details

The vulnerability allows a remote attacker to execute arbitrary code with the victim user's permissions.

The vulnerability exists due to an out-of-bounds read in Microsoft Office Word when processing a specially crafted document during export to PDF. A remote attacker can provide a malicious Word document and convince a user to open it and export it to PDF to execute arbitrary code with that user's permissions.

The Preview Pane is not an exploitation vector for this vulnerability.

Affected software

How to mitigate CVE-2026-109501

External References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2026-109501
• https://learn.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates

Related Security Bulletins

• Multiple vulnerabilities in Microsoft Office