CVE-2020-1023
A remote code execution vulnerability exists in Microsoft SharePoint when the software fails to check the source markup of an application package.
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (3.75%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
A remote code execution vulnerability exists in Microsoft SharePoint when the software fails to check the source markup of an application package. An attacker who successfully exploited the vulnerability could run arbitrary code in the context of the SharePoint application pool and the SharePoint server farm account. Exploitation of this vulnerability requires that a user uploads a specially crafted SharePoint application package to an affected version of SharePoint. The security update addresses the vulnerability by correcting how SharePoint checks the source markup of application packages.
- CVSS 3.1
- 8.8 HIGHCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
- EPSS
- 3.75% probability · 90th percentile
- Public exploits
- None in Exploit-DB
- CISA KEV
- Not listed
- Weakness
- CWE-434
- Affected
- microsoft/sharepoint enterprise server · microsoft/sharepoint foundation · microsoft/sharepoint server
- Source
- secure@microsoft.com
EPSS 3.7% since 26 October 2026; no change recorded yet. Points are recorded when the score first appears and whenever it moves by a percentage point or more.
References
Source: NVD record, EPSS from FIRST.org, KEV from CISA, exploits from Exploit-DB. Refreshed daily. Download this record as JSON.