SB2026051364 - Multiple vulnerabilities in Microsoft Excel

Description

This security bulletin contains information about 3 vulnerabilities.

1) Heap-based buffer overflow (CVE-ID: CVE-2026-40362)

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to a boundary error in Microsoft Excel. A remote attacker can trick a victim to open a specially crafted Office file, trigger a heap-based buffer overflow and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

2) Use-after-free (CVE-ID: CVE-2026-40359)

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to a use-after-free error in Microsoft Excel. A remote attacker can trick a victim to open a specially crafted Office file and execute arbitrary code on the system.

3) Out-of-bounds read (CVE-ID: CVE-2026-40360)

The vulnerability allows a remote attacker to gain access to potentially sensitive information.

The vulnerability exists due to a boundary condition in Microsoft Excel. A remote attacker can create a specially crafted file, trick the victim into opening it, trigger an out-of-bounds read error and read contents of memory on the system.

Remediation

Install update from vendor's website.

References

• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40362
• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40359
• https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-40360