CVE-2020-1147
Published: November 3, 2021
Official Description
Microsoft .NET Framework, Microsoft SharePoint, and Visual Studio contain a remote code execution vulnerability when the software fails to check the source markup of XML file input. Successful exploitation allows an attacker to execute code in the context of the process responsible for deserialization of the XML content.
CISA KEV Advisory
Microsoft .NET Framework, SharePoint, and Visual Studio Remote Code Execution Vulnerability
Microsoft .NET Framework, Microsoft SharePoint, and Visual Studio contain a remote code execution vulnerability when the software fails to check the source markup of XML file input. Successful exploitation allows an attacker to execute code in the context of the process responsible for deserialization of the XML content.
Apply updates per vendor instructions.
Risk Analysis
Microsoft .NET Framework, SharePoint, and Visual Studio are vulnerable to remote code execution due to improper XML file input validation. An attacker can execute code in the context of the process responsible for XML deserialization, posing a significant risk. Its high EPSS score of 0.93430 and inclusion in CISA's KEV indicate a high likelihood of exploitation.
This vulnerability is actively exploited in the wild. The flaw in checking XML file input allows for remote exploitation, likely through malicious XML content.
Administrators should apply the latest security updates for Microsoft .NET Framework, SharePoint, and Visual Studio. Implement robust input validation for XML files and restrict deserialization of untrusted data.
Technical Analysis
CVE-2020-1147 requires local access, meaning attackers must already have a foothold on the target system.
Exploitation requires some privileges, which limits the exposure to scenarios where an attacker has already gained initial access.
CISA has added CVE-2020-1147 to the Known Exploited Vulnerabilities (KEV) catalog, confirming active exploitation in the wild. U.S. federal agencies are required to patch this within the mandated timeframe, and all organizations should treat remediation as urgent.
Affected Vendors & Products
Exploit & PoC Resources
All References (1)
Quick Facts
Recommended Actions
- →Apply vendor patches immediately
- →Monitor CVE-2020-1147 in threat intel feeds
- →Review IDS/IPS signatures for exploitation attempts
- !CISA KEV: Federal agencies must patch per BOD 22-01 timeline
- !Active exploitation confirmed — treat as P1