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Cross-site scripting in Microsoft SharePoint Server enables spoofing

Priority LOW 21CWE-79Published · Updated

Key facts

Attack vector
Network
Privileges required
Low
User interaction
Required
Attack complexity
Low
Impact type
Cross-site scripting
Confidentiality · integrity · availability
Low · Low · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-79.

Summary

Microsoft SharePoint Server Subscription Edition from 16.0.0 before 16.0.20326.20190 is affected. Improper neutralization of input during web page generation (CWE-79) lets an authorized attacker perform spoofing over a network. The attack requires low privileges and user interaction.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

Description from the CNA

Improper neutralization of input during web page generation ('cross-site scripting') in Microsoft Office SharePoint allows an authorized attacker to perform spoofing over a network.

Why it matters now

Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00411 35th percentileScored 2026-11-07
Fix Fixed Microsoft SharePoint Server Subscription Edition (Microsoft): 16.0.20326.20190

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
None
Automatable
No
Technical impact
Partial

The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.

Affected products

VendorProductAffected versionsFixed inStatusSource
MicrosoftMicrosoft SharePoint Server Subscription Edition16.0.0 to before 16.0.20326.2019016.0.20326.20190Patch availableCNA
  • Microsoft SharePoint Server Subscription Edition VendorMicrosoft Affected 16.0.0 to before 16.0.20326.20190 Fixed in 16.0.20326.20190 Patch available CNA

CPE configurations NVD · 1

CPEVersionsRoleVendor
cpe:2.3:a:microsoft:sharepoint_server:*:*:*:*:subscription:*:*:*before 16.0.20326.20190VulnerableMicrosoft
  • cpe:2.3:a:microsoft:sharepoint_server:*:*:*:*:subscription:*:*:* Versions before 16.0.20326.20190 Vulnerable ·Microsoft

Remediation

Install version 16.0.20326.20190 of Microsoft SharePoint Server Subscription Edition, the fixed version.

Written with Claude Haiku 5.5 from the sources below · 2026-10-28

  • Fix · CNA Microsoft SharePoint Server Subscription Edition (Microsoft) Fixed in 16.0.20326.20190

Timeline

  1. 2026-10-13 Threatist record created from CVE-2026-102859
  2. 2026-10-13 Alias added: GHSA-q83g-f65q-ppc7
  3. 2026-10-14 CISA SSVC decision points changed

References

  • TI-2026-42212 Microsoft SharePoint Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-37256 Microsoft SharePoint Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 9.8
  • TI-2026-16982 Microsoft SharePoint Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 9.8
  • TI-2025-33671 Microsoft SharePoint Server Remote Code Execution Vulnerability KEVCVSS 3.1CRITICAL 9.8
  • TI-2023-13749 Microsoft SharePoint Server Elevation of Privilege Vulnerability KEVCVSS 3.1CRITICAL 9.8
  • TI-2019-00394 Improper input validation in Microsoft SharePoint Server KEVCVSS 3.1CRITICAL 9.8
See all 631 →

Sources