Microsoft SharePoint Server: Elevation of privilege via improper access control
Summary
Microsoft Office SharePoint Server Subscription Edition (on-premises) contains an improper access control flaw that allows an authorized attacker to elevate privileges over the network. The attacker needs a valid low-privilege account, but no user interaction is required. CVSS 8.8 (High), with high impact on confidentiality, integrity and availability.
Affected
- Microsoft SharePoint Server Subscription Edition 16.0.0 to below 16.0.20326.20190 (provisional, verify on MSRC)
- Other SharePoint editions: unknown
Fixed in
- October 13, 2026 security update KB5002927, build 16.0.20326.20190 or later
Workaround
- None documented by the vendor. Unknown.
Exploitation
- No evidence of in-the-wild exploitation found.
- Not listed in CISA KEV according to an automated alert; not confirmed on the CISA site.
- No public proof-of-concept exploit found.
- EPSS is low (about 0.7 to 2.0%, sources conflict).
Our recommendation
- Install KB5002927 as a priority; if SharePoint Workflow Manager is in use, install Workflow Manager KB5002799 on the farm first.
- Until patched, restrict external access to the farm and review accounts with low-privilege access.
- Enforce MFA and monitor for privilege changes and unusual account activity.
- Verify the affected version range on the MSRC advisory.
Information from Microsoft (Patch Tuesday October 2026)
- Severity (Microsoft)
- Important
- Impact
- Elevation of privilege – Microsoft Office SharePoint
- Status on Patch Tuesday
- Neither exploited nor publicly disclosed
- Exploitability assessment
- Exploitation less likely
- Product family
- Microsoft Office
- Updates (KB)
- KB5002927
Public exploits
PoC-in-GitHub, Metasploit and Exploit-DB list nothing for this CVE.
Research sources
- Microsoft Security Update Guide: CVE-2026-102860 msrc.microsoft.com
- Microsoft Support: SharePoint update KB5002927 support.microsoft.com
- Strix AI: CVE-2026-102860 www.strix.ai
- VulDB: CVE-2026-102860 vuldb.com
- Senserva: KB5002927 summary senserva.com
- Vulners: Rapid7 advisory CVE-2026-102860 vulners.com
Researched and written up in English and German by an AI (Claude by Anthropic) based on NVD, CISA, EPSS and the sources listed. The vendor information is authoritative. Researched on 31 Oct 2026, 19:26.
Original description (NVD)
Improper access control in Microsoft Office SharePoint allows an authorized attacker to elevate privileges over a network.
NVD references (1)
Sources
The tracker combines official, freely usable data sources – updated continuously:
- NVD (NIST) – CVEs, rating (CVSS), affected products
- CISA KEV – vulnerabilities confirmed by CISA as actively exploited
- CISA Vulnrichment – CISA assessment (SSVC) in the official CVE record
- FIRST EPSS – probability of exploitation
- Microsoft MSRC – Patch Tuesday: vulnerabilities, severity, updates
- PoC-in-GitHub – public proof-of-concept repositories
- Metasploit (Rapid7) – modules of the Metasploit Framework
- Exploit-DB (OffSec) – archive of public exploits (links only)
- Patch days: official vendor pages (linked per vendor) (Vendor patch days)
This product uses data from the NVD API but is not endorsed or certified by the NVD. EPSS data © FIRST.org.
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