Heap-based buffer overflow in Microsoft 365 Apps for Enterprise and Microsoft Office - CVE-2026-80087

Vulnerability details

The vulnerability allows a remote attacker to disclose sensitive information.

The vulnerability exists due to a heap-based buffer overflow in Microsoft Office when processing content received over a network. A remote attacker can exploit the heap-based buffer overflow to disclose sensitive information.

User interaction is required. The Preview Pane is not an attack vector.

Affected software

How to mitigate CVE-2026-80087

External References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2026-80087
• https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates

Related Security Bulletins

• Multiple vulnerabilities in Microsoft Office