Out-of-bounds read in Microsoft products - CVE-2026-78520

Vulnerability details

The vulnerability allows a remote attacker to disclose sensitive information.

The vulnerability exists due to an out-of-bounds read in Microsoft Office Outlook when displaying content in the Preview Pane. A remote attacker can exploit the vulnerability to disclose sensitive information.

Affected software

How to mitigate CVE-2026-78520

External References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2026-78520
• https://docs.microsoft.com/en-us/officeupdates/microsoft365-apps-security-updates

Related Security Bulletins

• Multiple vulnerabilities in Microsoft Office