High severity · published Oct 13, 2026
CVE-2026-102866
Microsoft Office SharePoint Elevation of Privilege Vulnerability
8.1
CVSS
0.7%
EPSS
No
On KEV
Description
Improper verification of cryptographic signature in Microsoft Office SharePoint allows an unauthorized attacker to elevate privileges over a network.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.7% · higher than 52% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
SH
SharePoint · Microsoft
before 16.0.20326.20190 · source: NVD
MS
Microsoft SharePoint Server Subscription Edition · Microsoft
16.0.0 before 16.0.20326.20190 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-102866
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-102866
vendor-advisory
https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-102866
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