Out-of-bounds read in Microsoft products - CVE-2026-118300

Vulnerability details

The vulnerability allows a remote attacker to disclose information from small portions of stack memory.

The vulnerability exists due to an out-of-bounds read in Microsoft Office Excel when processing input that causes access beyond a memory boundary. A remote attacker can supply crafted input that, with user interaction, triggers the out-of-bounds read to disclose information from stack memory.

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

Affected software

How to mitigate CVE-2026-118300

External References

• https://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2026-118300
• https://support.microsoft.com/help/5002946

Related Security Bulletins

• Multiple vulnerabilities in Microsoft Office