CVE-2026-66805

HIGH

Deserialization of untrusted data in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.

CVSS v3.1 Score

8.8
HIGH
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack Vector
NETWORK
Complexity
LOW
Privileges
LOW
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
HIGH
Integrity
HIGH
Availability
HIGH
Published: 8/11/2026Modified: 10/21/2026

Related Intelligence (1)

CRITICALZero Day

Patch Tuesday - August 2026

Microsoft is publishing 421 vulnerabilities on August 2026 Patch Tuesday , including 236 vulnerabilities in Windows. This is lower volume than last month’s record-breaking behemoth, but still one of the largest Patch Tuesday totals ever. There is no reason to suppose that Patch Tuesday will ever return to the lower volumes we saw prior to 2026. Microsoft is aware of exploitation in the wild for on

CVE-2026-63520CVE-2026-55040
Rapid7

References (1)

https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-66805PatchVendor Advisory