CVE-2026-85900: CWE-502: Deserialization of Untrusted Data in Microsoft Microsoft SharePoint Server Subscription Edition
Description
CVE-2026-85900 is a high-severity vulnerability in Microsoft SharePoint Server Subscription Edition involving deserialization of untrusted data. This flaw allows an authorized attacker to execute arbitrary code remotely over a network. The vulnerability affects versions from 16.0.0 up to but not including 16.0.20326.20190. An official fix is available from Microsoft to address this issue.
CVSS v3.1
Score 8.8high
Affected software
Microsoft
Microsoft SharePoint Server Subscription Edition
Weaknesses
AI-Powered Analysis
Machine-generated threat intelligence
Technical Analysis
This vulnerability (CVE-2026-85900) in Microsoft SharePoint Server Subscription Edition is caused by improper handling of deserialization of untrusted data. An attacker with authorized access can exploit this flaw to execute arbitrary code remotely, potentially leading to full compromise of the affected system. The CVSS 3.1 base score is 8.8, reflecting high impact on confidentiality, integrity, and availability. The vulnerability affects versions >=16.0.0 and <16.0.20326.20190. Microsoft has released an official fix to remediate this issue.
Potential Impact
Successful exploitation allows an authorized attacker to execute arbitrary code remotely on the vulnerable SharePoint server. This can lead to complete system compromise, including unauthorized access, data modification, and service disruption.
Mitigation Recommendations
An official fix is available from Microsoft. It is recommended to apply the security update for Microsoft SharePoint Server Subscription Edition to versions 16.0.20326.20190 or later. No additional mitigation steps are indicated by the vendor advisory.
Technical Details
- Data Version
- 5.2
- Assigner Short Name
- microsoft
- Date Reserved
- 2026-09-04T18:21:15.992Z
- Cvss Version
- 3.1
- State
- PUBLISHED
- Remediation Level
- official-fix
- Vendor Advisory Urls
- [{"url":"https://msrc.microsoft.com/update-guide/vulnerability/CVE-2026-85900","vendor":"Microsoft"}]
Threat ID: 6ace854a2cdf04f6569fec67
Added to database: 10/13/2026, 19:23:54 UTC
Last enriched: 10/14/2026, 02:49:38 UTC
Last updated: 10/14/2026, 02:49:38 UTC
Views: 2
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