CVE-2026-20963
Microsoft SharePoint Remote Code Execution Vulnerability
- Critical 9.8
- Exploited: added to CISA KEV 18 Mar 2026
Description
Deserialization of untrusted data in Microsoft Office SharePoint allows an unauthorized attacker to execute code over a network.
Key facts
- Published
- 13 Jan 2026
- Last changed
- 30 Jul 2026
- Assigned by
- microsoft
- KEV added
- 18 Mar 2026
- KEV fix due
- 21 Mar 2026
- EPSS
- 29.201% likely to be exploited in the next 30 days, higher than 98.201% of CVEs (scores for 15 Nov 2026)
- SSVC (CISA)
- Exploitation: active; Automatable: yes; Technical impact: total
Severity scores
Each score is shown as its source gave it. They are not averaged or merged.
- 9.8CVSS 3.1, Criticalfrom the CNA (microsoft)
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
What to do
- 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 KEV required action
Historical context and remediation
This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.
No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.
Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.
Affected products
| Vendor | Product | Versions |
|---|---|---|
| Microsoft | Microsoft SharePoint Enterprise Server 2016 |
|
| Microsoft | Microsoft SharePoint Server 2019 |
|
| Microsoft | Microsoft SharePoint Server Subscription Edition |
|
Timeline
- 13 Jan 2026 Published
- 18 Mar 2026 Added to the CISA KEV catalogue