Critical CVSS 9.9 EPSS 0.0176 2020-09 archive

Executive Summary

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.

Overview

9.9
CVSS CRITICAL
Critical
MS Severity
Not Exploited
MS Exploit Status
Less Likely
MS Exploit Likelihood
Category Remote Code Execution
Released Sep 8 2020
Last Updated Sep 8 2020
Publicly Disclosed No
CISA KEV Not Listed
Known Exploits None Known
EPSS Score 0.0176 — 0.75076 percentile
NVD CVSS 9.9 CRITICAL — matches MSRC

CVSS Vector

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C
ATTACK VECTOR
Network
ATTACK COMPLEXITY
Low
PRIVILEGES REQUIRED
Low
USER INTERACTION
None
SCOPE
Changed
CONFIDENTIALITY
High
INTEGRITY
High
AVAILABILITY
High
EXPLOIT CODE MATURITY
Proof-of-Concept
REMEDIATION LEVEL
Official Fix
REPORT CONFIDENCE
Confirmed
Temporal Score: 8.9

EPSS Score

0.0176
probability of exploitation in the next 30 days
0.75076 percentile - updated 2026-06-21
View on FIRST.org

Affected Products

3 affected products
Product KB Article Severity Impact Restart Required
Microsoft Business Productivity Servers 2010 Service Pack 2 3101523 (Security Update) Critical Remote Code Execution Maybe
Microsoft SharePoint Enterprise Server 2013 Service Pack 1 4484480 (Security Update) Critical Remote Code Execution Maybe
Microsoft SharePoint Enterprise Server 2016 4484506 (Security Update) 4484512 (Security Update) Critical Remote Code Execution 4484473 4484476 Base: 9.9 Temporal: 8.9 Vector: CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:P/RL:O/RC:C Maybe 4484506 Microsoft SharePoint Server 2010 Service Pack 2 4486664 (Security Update) Critical Remote Code Execution Maybe

Patches

3 patches
Article Type Restart
3101523 Security Update Maybe
4484480 Security Update Maybe
4486664 Security Update Maybe

Known Exploits

Acknowledgments