Read the docs
TI-2026-39747 Aliases CVE-2026-55040GHSA-grxw-7cvc-96rv

Microsoft SharePoint Server Security Feature Bypass Vulnerability

Priority CRITICAL 98Exploited in the wildCWE-1390Published · Updated

Key facts

Attack vector
Network
Privileges required
None
User interaction
None
Attack complexity
Low
Impact type
Security bypass
Confidentiality · integrity · availability
High · High · None
Fix status
Fixed

Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Microsoft. Impact type from Microsoft.

Summary

Weak authentication in Microsoft Office SharePoint allows an unauthorized attacker to bypass a security feature over a network.

Why it matters now

Exploitation Active In CISA KEV since 2026-08-18CISA due date 2026-08-21
EPSS 0.69536 99th percentileScored 2026-11-07
Public exploit Yes 2 exploit referencesTagged by NVD
Fix Fixed Microsoft: 3 updates

SSVC decision points

CISA ADP · SSVC 2.0.3

Exploitation
Active
Automatable
Yes
Technical impact
Total

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 Enterprise Server 201616.0.0 to before 16.0.5561.100116.0.5561.1001Patch availableCNA
MicrosoftMicrosoft SharePoint Server 201916.0.0 to before 16.0.10417.2017516.0.10417.20175Patch availableCNA
MicrosoftMicrosoft SharePoint Server Subscription Edition16.0.0 to before 16.0.19725.2043416.0.19725.20434Patch availableCNA
  • Microsoft SharePoint Enterprise Server 2016 VendorMicrosoft Affected 16.0.0 to before 16.0.5561.1001 Fixed in 16.0.5561.1001 Patch available CNA
  • Microsoft SharePoint Server 2019 VendorMicrosoft Affected 16.0.0 to before 16.0.10417.20175 Fixed in 16.0.10417.20175 Patch available CNA
  • Microsoft SharePoint Server Subscription Edition VendorMicrosoft Affected 16.0.0 to before 16.0.19725.20434 Fixed in 16.0.19725.20434 Patch available CNA

CPE configurations NVD · 3

CPEVersionsRoleVendor
cpe:2.3:a:microsoft:sharepoint_server:*:*:*:*:subscription:*:*:*before 16.0.19725.20434VulnerableMicrosoft
cpe:2.3:a:microsoft:sharepoint_server:2016:*:*:*:enterprise:*:*:*2016VulnerableMicrosoft
cpe:2.3:a:microsoft:sharepoint_server:2019:*:*:*:*:*:*:*2019VulnerableMicrosoft
  • cpe:2.3:a:microsoft:sharepoint_server:*:*:*:*:subscription:*:*:* Versions before 16.0.19725.20434 Vulnerable ·Microsoft
  • cpe:2.3:a:microsoft:sharepoint_server:2016:*:*:*:enterprise:*:*:* Versions 2016 Vulnerable ·Microsoft
  • cpe:2.3:a:microsoft:sharepoint_server:2019:*:*:*:*:*:*:* Versions 2019 Vulnerable ·Microsoft

Remediation

Microsoft 3 updates

  • KB5002891
    Security Update
    • Microsoft SharePoint Enterprise Server 2016 16.0.5561.1001
  • KB5002883
    Security Update
    • Microsoft SharePoint Server 2019 16.0.10417.20175
  • KB5002882
    Security Update
    • Microsoft SharePoint Server Subscription Edition 16.0.19725.20434

Vendor assessments

Microsoft

Microsoft's page for this CVE →

Impact
Security Feature Bypass
Exploited
No
Publicly disclosed
No
Exploitability
Exploitation More Likely

Timeline

  1. 2026-08-18 Added to CISA KEV
  2. 2026-10-02 Threatist record created from CVE-2026-55040
  3. 2026-10-03 Alias added: GHSA-grxw-7cvc-96rv
  4. 2026-10-05 EPSS moved to the 99th percentile and above

References

Exploit 2

Patch 1

  • 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

This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences