Microsoft Security Update Guide · SharePoint
Microsoft SharePoint Server 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 Critical.
- No attacks reported yet, but Microsoft expects exploitation to be likely.
- What should you do? Install the security update for the version you run (or a later cumulative update):
- Microsoft SharePoint Server Subscription Edition: KB5002893
16.0.19725.20522 - Microsoft SharePoint Server 2019: KB5002894
16.0.10417.20198 - Microsoft SharePoint Server 2019: KB5002896
16.0.10417.20198
- Microsoft SharePoint Server Subscription Edition: KB5002893
- This applies to SharePoint Server you run yourself. Microsoft updates SharePoint Online in Microsoft 365.
Deserialization of untrusted data 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-502: Deserialization of Untrusted Data
The software turns received data into objects without checking it. With crafted data an attacker can get code to run.
Key facts
Released
11 aug 2026
Impact
Remote Code Execution
Max severity
Critical
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 More 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 | KB5002893 · Security Update | 16.0.19725.20522 |
| Microsoft SharePoint Server 2019 | KB5002894 · Security Update | 16.0.10417.20198 |
| Microsoft SharePoint Server 2019 | KB5002896 · Security Update | 16.0.10417.20198 |
FAQ
- How could an attacker exploit the vulnerability?
- In a network-based attack, an authenticated attacker, as at least a Site Owner, could write arbitrary code to inject and execute code remotely on the SharePoint Server.
- 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 | 11 aug 2026 | Information published. |
What changed in Microsoft 365 this week? →
View at Microsoft → ← All security advisories
Source: Microsoft Security Update Guide. 365Fanatic is not affiliated with Microsoft.
