Microsoft Security Update Guide · SharePoint
Microsoft Office SharePoint Remote Code Execution Vulnerability
Published
What does this mean?
- Remote Code Execution. An attacker can run their own code on the system remotely. This is the most serious type: it can lead to taking over the system.
- It can be exploited over the network (including from the internet if the service is reachable there), with an ordinary user account and without any user action.
- CVSS 8.8 out of 10: high. Microsoft rates it Important.
- No attacks reported; Microsoft expects exploitation to be less likely.
- What should you do? Install the security update for the version you run (or a later cumulative update):
- Microsoft SharePoint Server Subscription Edition: KB5002908
16.0.20326.20082
- Microsoft SharePoint Server Subscription Edition: KB5002908
- This applies to SharePoint Server you run yourself. Microsoft updates SharePoint Online in Microsoft 365.
Improper access control in Microsoft Office SharePoint allows an authorized attacker to execute code over a network.
SharePoint Office / Microsoft 365 Apps
How do I check if I am affected?
SharePoint Server: check and update
- Check your farm build in the SharePoint Management Shell:
Or in Central Administration → Upgrade and Migration → Check product and patch installation status.(Get-SPFarm).BuildVersion - If the build is equal to or higher than the build under "Affected products and updates" below, this vulnerability is fixed. A later cumulative update includes the fix too.
- Otherwise install the update on every server in the farm, then run the SharePoint Products Configuration Wizard, or:
PSConfig.exe -cmd upgrade -inplace b2b -wait -cmd applicationcontent -install -cmd installfeatures -cmd secureresources -cmd services -install - You do not need to update SharePoint Online in Microsoft 365; Microsoft does that.
What kind of flaw is this?
- CWE-284: Improper Access Control
Access to a function or data is not properly restricted.
Key facts
Released
8 sep 2026
Impact
Remote Code Execution
Max severity
Important
Weakness
CVSS 3.1
8.8 / 7.7 (base / temporal)
Vector string
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:CPublicly disclosed
No
Exploited
No
Exploitability assessment
Exploitation Less Likely
Customer action required
Yes
Links
CVSS metrics
| Base score metrics | |
|---|---|
| Attack Vector | Network |
| Attack Complexity | Low |
| Privileges Required | Low |
| User Interaction | None |
| Scope | Unchanged |
| Confidentiality | High |
| Integrity | High |
| Availability | High |
| Temporal score metrics | |
| Exploit Code Maturity | Unproven |
| Remediation Level | Official Fix |
| Report Confidence | Confirmed |
Affected products and updates
| Product | Update | Build |
|---|---|---|
| Microsoft SharePoint Server Subscription Edition | KB5002908 · Security Update | 16.0.20326.20082 |
FAQ
- How could an attacker exploit this vulnerability?
- An attacker could exploit the vulnerability by leveraging vulnerable APIs through a deserialization of unsafe data input vulnerability. Exploitation of this vulnerability requires that a user access a susceptible API on an affected version of SharePoint with specially-formatted input, resulting in possible remote code execution on the SharePoint Server.
- I am running SharePoint Server 2016. Do the updates for SharePoint Enterprise Server 2016 also apply to the version I am running?
- Yes. The same KB number applies to both SharePoint Server 2016 and SharePoint Enterprise Server 2016. Customers running either version should install the security update to be protected from this vulnerability.
- There are multiple update packages available for some of the affected software. Do I need to install all the updates listed in the Security Updates table for the software?
- Yes. Customers should apply all updates offered for the software installed on their systems. If multiple updates apply, they can be installed in any order.
Revisions
| Version | Date | Note |
|---|---|---|
| 1 | 8 sep 2026 | Information published. |
This is in the weekly digest for week 37 · What changed this week? →
View at Microsoft → ← All security advisories
Source: Microsoft Security Update Guide. 365Fanatic is not affiliated with Microsoft.
