CVE-2026-20963: Microsoft SharePoint Deserialization of Untrusted Data
This Microsoft advisory covers CVE-2026-20963 in Microsoft SharePoint Enterprise Server 2016, Microsoft SharePoint Server 2019 and Microsoft SharePoint Server Subscription Edition.
- CVE-2026-20963
Key facts
- Vendor rating
- Critical, CVSS 9.8
- CISA KEV
- Listed ; federal due date
- Affected
- Microsoft SharePoint Enterprise Server 2016 16.0.0 before 16.0.5535.1001; Microsoft SharePoint Server 2019 16.0.0 before 16.0.10417.20083; Microsoft SharePoint Server Subscription Edition 16.0.0 before 16.0.19127.20442
- Fixed in
- 16.0.5535.1001, 16.0.10417.20083, 16.0.19127.20442
- Source published
- Source revised
- Listed by VulniPulse
Compiled by VulniPulse from the linked sources. How records are collected and checked.
Affected products & platforms
CVE-2026-20963 in the CISA Known Exploited Vulnerabilities catalog
- CISA name:
- Microsoft SharePoint Deserialization of Untrusted Data Vulnerability
- CISA description:
- Microsoft SharePoint contains a deserialization of untrusted data vulnerability that allows an unauthorized attacker to execute code over a network.
- Required action:
- Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Description
Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.
Affected products named by the advisory: Microsoft SharePoint Enterprise Server 2016; Microsoft SharePoint Server 2019; Microsoft SharePoint Server Subscription Edition.
Text from the source record.
- Microsoft SharePoint Enterprise Server 2016 16.0.0 before 16.0.5535.1001
- Microsoft SharePoint Server 2019 16.0.0 before 16.0.10417.20083
- Microsoft SharePoint Server Subscription Edition 16.0.0 before 16.0.19127.20442
Official advisory · high-confidence parse· fetched ·verify at source
How to fix CVE-2026-20963
Upgrade to a fixed release named by Microsoft:
- 16.0.5535.1001
- 16.0.10417.20083
- 16.0.19127.20442
End-of-life dates for Microsoft SharePoint Server
More Microsoft Server advisories
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Microsoft Server advisories, January 2026All Microsoft Server advisories
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