Actively exploited · Published Jan 13, 2026 · Assigned by microsoft
CVE-2026-20963Microsoft SharePoint Remote Code Execution Vulnerability
Critical 9.8 Exploited
In plain English
A critical-severity unsafe deserialization in Microsoft SharePoint Enterprise Server 2016 from Microsoft. Attackers are actively exploiting it in the wild (listed by CISA on March 18, 2026). The chance it is exploited in the next 30 days is estimated at 29.2% (higher than 98% of all known vulnerabilities). Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
CISA guidance
Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.
Federal agencies must remediate by Mar 21, 2026.
Official description
Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| Microsoft | Microsoft SharePoint Enterprise Server 2016 | 16.0.0 – before 16.0.5535.1001 |
| Microsoft | Microsoft SharePoint Server 2019 | 16.0.0 – before 16.0.10417.20083 |
| Microsoft | Microsoft SharePoint Server Subscription Edition | 16.0.0 – before 16.0.19127.20442 |
Weakness: CWE-502 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
References
- Microsoft SharePoint Remote Code Execution Vulnerability vendor-advisory, patch
- https://www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2026-20963 government-resource