CVE-2026-40357
HighMicrosoft SharePoint Server Remote Code Execution Vulnerability
Published May 12, 2026 · Updated Aug 10, 2026 · Also known as EUVD-2026-29639, GHSA-9wcj-vxr2-vvvh
Key Facts
Patch in the next maintenance window- CVE-2026-40357 is a high-severity vulnerability (CVSS 8.8 v3.1) affecting Sharepoint Server (Microsoft), Sharepoint Server 2016 (Microsoft), Sharepoint Server 2019 (Microsoft) and 2 more products.
- It is not listed in any known-exploited vulnerabilities catalog. No public exploit code is known.
- EPSS estimates a 2.3% probability of exploitation in the next 30 days.
- Fixed versions are available, including Microsoft SharePoint Enterprise Server 2016 16.0.5552.1002, Sharepoint Server 16.0.19725.20280, Sharepoint Server 2019 16.0.10417.20128.
- Brandefense priority: patch in the next maintenance window, because of its high severity, although no exploitation is known.
CVSS v3.1
8.8
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS (30-day exploit likelihood)
2.3%
Exploited in the wild
No known
Not in a known-exploited catalog
Public exploit code
None known
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Description
Deserialization of untrusted data in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.
Affected Products
12 affected entries in total| Product | Affected versions | Fixed in |
|---|---|---|
| Sharepoint ServerMicrosoft | 2016, 2019 | 16.0.19725.20280 |
| Sharepoint Server 2016Microsoft | See advisory | n/a |
| Sharepoint Server 2019Microsoft | >= 16.0.0 | 16.0.10417.20128 |
| Microsoft SharePoint Enterprise Server 2016 | >= 16.0.0 | 16.0.5552.1002 |
| Microsoft SharePoint Server Subscription Edition | >= 16.0.0 | 16.0.19725.20280 |
Patched Releases
Microsoft SharePoint Enterprise Server 2016
16.0.5552.1002
Sharepoint Server
16.0.19725.20280
Sharepoint Server 2019
16.0.10417.20128
Microsoft SharePoint Server Subscription Edition
16.0.19725.20280
Timeline
Publicly disclosed
May 12, 2026
Last updated
Aug 10, 2026
Weakness Type
- CWE-502 Deserialization of Untrusted Data
References
FAQ
Common Questions.
Deserialization of untrusted data in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.
Affected: Sharepoint Server (Microsoft) versions 2016, 2019; Sharepoint Server 2016 (Microsoft); Sharepoint Server 2019 (Microsoft) versions >= 16.0.0, among others. The full list is in the CVE brief.
It is not listed in any known-exploited vulnerabilities catalog.
No, it is not currently listed in the CISA Known Exploited Vulnerabilities catalog.
No public exploit code is known.
Fixed versions are available, including Microsoft SharePoint Enterprise Server 2016 16.0.5552.1002, Sharepoint Server 16.0.19725.20280, Sharepoint Server 2019 16.0.10417.20128.
Brandefense priority: patch in the next maintenance window, because of its high severity, although no exploitation is known.
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